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Before I start this comparison I must state a few points upfront:

1. This is not going to determine which watch is the ?best? as that is subjective to say the least.

2. Neither will this be an in-depth review of either watch.




This will review will however compare the watches in terms of the:

- Design
- Function
- Feel (how they wear)

One final comment, it is apparent to those who know me I?m an ardent fan of both Mr Platts and Mr Yao watches.


The PRS-18Q

Eddie has been very successful at creating the re-editions of the Precista military watches for a number of years. The PRS-18Q is the latest addition and is a model that was issued to the military around 1989 until 1993 with the ordnance numbers 6645-99, 757-3314. To compliment the quartz version an automatic is also available. There have been a few updates made to the initial design to keep with the changes in today?s technologies, one such being the upgrade to a sapphire crystal.

Specs - PRS-18Q

Case width (inc crown) = 43.5 mm
Case Thickness = 12.5 mm
Case length (lug to lug) = 47.5 mm
Lug width = 20.0 mm
Weight = 80 grams
Crystal = 3mm Sapphire AR
Case Finish = Bead blasted
Anti-magnetic = 4800 A/m
Water resistance = 300 meters
Bezel = 120 clicks
Luminous = Super Luminova C3


Bill has been known basically for his custom dial / hands etc that can be installed into both Swiss and Seiko movement based watches. His first in-house watch was the Quad 10 and the second has been the MMT Blackwater, which is based on the original Benrus models from the 70's and 80's. Again like the PRS-18Q, Bills watches have been tweaked where necessary and for the MMT the crystal has also been updated to a sapphire.



Specs - MMT

Case width (inc crown) = 43.2 mm
Case Thickness = 13.3 mm
Case length (lug to lug) = 47.5 mm
Lug width = 20.0 mm
Weight = 72 grams
Crystal = Double domed sapphire AR
Case Finish = Fine sandblasted finish
Anti-magnetic = N/K
Water resistance = 200 meters
Bezel = 120 clicks
Luminous = SuperLumiNova

Please note the there is an automatic version of the PRS-18, this differs slightly from the quartz version as it is 10grams heavier weighing in at 90grams.



Both the PRS-18 and MMT look almost identical on paper plus share a very similar style of case, but that is where the similarities end. Viewing the side profile of each watch the first major difference is obvious, the PRS-18 has a very distinct square bezel (rather like the Marathon SAR), whereas the MMT has a much curved profile. This will be examined in further detail later in the review.

The second major difference is the dial and hands of each watch that are completely different. The PRS-18 dial and hands are a faithful reproduction of the original Precista, which are very easy to read. The huge 12 o?clock marker is easily readable in day light and extremely readable at night when fully charged, make no mistake it?s rather like a beacon! The 5 minute markers are more than adequate for both night and day visibility. The skeleton hands more than compliment the dial in terms of readability. There is no day or date on the PRS-18, I can only deduce that there was no day or date on the original. The lume is great and although not fully charged and timed is fantastic for a watch of any price range.

The final difference is that the PRS-18 is rated to 300m, whilst the MMT is rated to 200m. Both more than sufficient for desk diving!

The MMT differs when it comes to the dial and hands as Bill has made this watch so any number of combinations can be made with his dials and hands. I did read that there was over several thousand possible combinations however most people select a traditional Benrus look-a-like: My one is in that vein apart from the seconds hand having a red tip. The type 1 dial has been seen on many a watch over the years and full testament to the design it is one of the easiest to read. This dial paired with the type 1 (ladder) hands is almost perfect on the eye. The MMT on review does not contain a date window however other options can facilitate this function should it be required by the wearer. As for the lume, the MMT is just as readable by night as by day, the lume being one of the stronger in the watch industry just like the PRS-18.


The accuracy of both watches is not reviewed here as it is automatic Vs quartz. However it is worth noting that whilst the PRS-18A has the standard ETA 2824 movement, the MMT has the elaboree grade of movement. As far as the difference between them this is what I have been able to discover:

ST - Standard (also with Etachoc shock protection and ETASTABLE)
EL - Élaborée (with Incabloc shock protection and basic decoration)


One comment on the PRS-18Q that has come up on the TZ-UK forum is that on the quartz the second hand does not strike the seconds markers. There has been some good explanation for this phenomonen; I understand it is common in Swiss quartz movements. My one comment would be that having been an owner of several 80s Seiko quartz divers watches (7548 series) all of the ones I owned hit the minute markers bang on, so one illustration of where Japanese engineering differs from Swiss.


The operation of the crown is not only essential for waterproofing but the means to set the watch. The MMT has a smaller compared to the PRS-18, however both crowns fit well with the overall case design. The operation of the MMT for setting the time is as per normal, but when you are screwing Norske eiere, nordmenn i staben og et flott produkt gjor dem til et av de selvfolgelige casino -valgene. the crown back onto the case threads you need to take care. I am not saying that the crown and threads are designed / manufactured wrong or out of tolerance, but they do not seem to line up as easily as a Seiko 6309 would. So there would be a potential / possibility for a crossed thread if you were not concentrating on what you were doing. One tip that I came across that I practice is that when I close the crown I turn the crown the reverse direction until the threads line up and then start to screw the crown closed. The PRS-18 crown however works flawlessly, it opens smartly when you unwind the crown and setting the time is as per normal. When you close the crown it engages the case threads as you would expect a finely engineered screw thread.




Although the bezel inlays are different the focus here is on the operation not so much the difference between diver and GMT, in addition the MMT has three options of bezel inserts. To start with both watches employ a 120 click bezel; however there is a difference here between the watches. The MMT has a smooth equal 120 click whereas the PRS-18 has an unequal 120 click; it is like a big click and a smaller click. When you first operate the PRS-18 bezel it feels like a 60 click bezel as you only hear and feel the 60 bigger clicks, but rotate it slowly and you will indeed hear 120 clicks. I imagine that there are two springs under the bezel of slightly different thickness, which would explain this.

The looks of each bezel is also very different, the PRS-18 has a very distinct square bezel (rather like the Marathon SAR), with really nice deep grooves in that make it easy to grip and very easy to rotate. I expect that if I were wearing diving gloves that this bezel would be a breeze to turn. The MMT bezel is very slim allowing for the curved profile of the crystal, but has smaller but sharper edges. If I were wearing divers gloves this may be harder to turn considering it has a smaller, more discrete edges to the bezel.

As a final note on the bezels, both watches contain lume at the 12 o?clock positions.

In recent months there has been a new modification to the MMT, Bill Yao has released the MMT with a different bezel set up featuring a bezel very similar to the SAR / PRS-18. 



I can only deduce from this that has been created to compete with the SARs / PRS-18s of the world, as it does break away from the Benrus connection.

Lastly both watches are fitted with spring bars with the watch lugs being drilled through to add to the ease of changing straps. The MMT has been sold in VERY limited numbers (I believe less than 5) with fixed bars to keep close to the Benrus tradition. There is no bracelet option for either watch; instead the wearer has the option of any standard 20mm strap, with the NATO / Zulu type of strap seems to be the more commonly favored.

Feel (how they wear)

The PRS-18 and MMT were worn on the various types of NATO/Zulu straps available: 2 piece / 2 ring / 4 ring. My own preference is the 2 piece strap as it reduces the height the watch off of the wrist and brings the case back in contact with the wearer?s wrist, where the 2 & 4 ring NATOs do not. However this is all depends on the wearer?s personal preference.

Viewing the case backs of each watch there is also the visual difference as with the upper part of the watches. The PRS-18 retains a ver square and angular case back. The MMT has a very curved case back in keeping with the Benrus style. The PRS-18 has engraved lettering whilst the MMT has a laser etched lettering. 



On the wrist both these watches feel almost identical; it really is tough to actually determine which watch you are wearing. Both watches are very easy and comfortable to wear, mainly due to the low(ish) weight and how a NATO strap makes them fit nice and snug to the wrist. Looking at the lug-to-lug length they are the same for both and I would suggest is suitable for most size of wrists.

Despite the fact that the MMT has a case thickness 0.8mm more than the PRS-18; the latter has more presence when you view them from the side. This picture is slightly deceiving as the lugs on the PRS-18 create the illusion of it being thicker



Although the side profiles is the main difference between the PRS-18 and the MMT they both wear well with a shirt. Neither has a problem of getting caught up on the shirt cuffs. If you have ever had a large divers watch (like a G-shock) with a shirt you know what I mean.


When I re-visit the reasons that made the MMT the watch of the year for me I felt I had to apply them to the PRS-18. The three reasons were: the look, readability & how it wears.

Look - Both watches have just the right proportions (case, crystal, bezel, dial & hands), which makes them pleasant watch just to look at.

Readability - Both watches are easily readable: No clutter like sub-dials, date windows, heaven forbid a cyclops on the crystal. No crap on the dial like ?automatic, 10,000m, first watch on the moon & also makes the toast. They are just very simple and understated.

How it wears - Both watches are really well balanced and easy to wear watch. The low profile makes each watch easy to wear with any long sleeved garment, no catching on shirt cuffs etc.

Simply I have to say that looking at the reasons above I could have written the same review for the PRS-18 and all I would have to do is substitute the name PRS-18 for MMT!

So what one do you buy?

Both the PRS-18 and MMT fall in the category of ?you must have one of these in your collection?.

The only minor drawback I have found with the MMT is that the crown may be a weak point over time. Similarly the only minor drawback I have found with the PRS-18 is that the bezel click is not equal on the complete 120 clicks (60 strong and 60 weak). These are not show stoppers for any potential watch purchase, just little nit-pickings if anything!

So at the end of the day the one you get will be based on a very personal taste, i.e. what you like the look of most.!

They both represent extraordinary value for money, the PRS-18 even more so. The current prices of the watch are as follows:

PRS-18Q = £140
PRS-18A = £180
MMT = £227 (Jan 07 exchange rate) / $450. This is the base price, optional AR coating is extra.

More information

For further details of the watches here please visit the owners web pages:

PRS-18 care of Eddie Platts at http://www.timefactors.co.uk

MMT care of Bill Yao at http://www.mkiiwatches.com

deano :D

The rights of ownership of the photos contained in this review remain with the original owner and have been shown for reference / illustration purposes only.

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