Reddit mentions of Casio Men's GD350-1B G Shock Black Watch

G-Shock 100%. There are a couple military ones with blacked out reverse dials, however they can be more difficult to see in certain light conditions than the normal dials. Here are a few models that military personnel use and some others:

GD-120

DW6900BB-1

DW6900-1V: This one is similar to a very popular G-shock used by a lot of US military, the DW-6600. I don't think they make it anymore though, but this is pretty close.

GW6900-1

GD100-1BCR

GD-120CM

GD-400

GD350-1B: This one has a yellowish tint to the digits so it's one of the easier reverse dials to read.

Mudman

Rangeman

DW5600MS-1CR: For this one there is a really cool mod you can do for about $35 more to make it look really tactial and military.

Edit Added some stuff

Hey! not in the CAF but a huge watch nerd.

The Casio GD350-1B is a pretty good choice. It's a G-shock and has pretty much every feature you need (Countdown, timezone, calendar, stopwatch). The unique thing about this model is that it has a silent vibration alarm and a negative display.

The Casio F-91W It does lake some features but its probably one of the most well-known, cheap, and reliable Casio watch out there. It's really light, pretty much not noticeable, and is almost impossible to break.

The Casio G-Shock DW5600E-1V is a really cheap but it still packs bunch of features and it is durable. I guess this is the middle between the GD 350 and the F-91.

There are bunch of really good and durable watches out there, these are just some of my personal favourites. They are not only reliable, durable, and good watches, they look really nice too.

I'd say there are three main options:

1. Cheap Casio
   
   
2. Ironman
   
   
3. Gshock or this other Gshock with a pager motor that can alarm silently

In that case, I would recommend this Rangeman. Listed at $225 (randomly, your limit) but I'm sure you could offer around $200 and make a deal.

That's much nicer than the regular rangeman, too. Carbon fiber band an a metal keeper. (Those are basically the only two improvements over the regular Rangeman.) That's worth the little extra you'd pay though.

If that doesn't work for you, then in my order of preference for a military bf:

1. regular Rangeman
   
2. regular Mudman (between 1 and 2 might depend on his branch).
   
3. This GD-350. Round but not too round. Black with negative display. Bigger numbers, and the updated neg. display (more readable). (also only $100). (this one is on my short list).
   
   There are a bunch of other models, and basically any of them would fit your qualifications. Pick the one you like seeing him in best! :)

The best negative display currently available would probably be the GD350-1B.

There's a G-Shock for that: https://www.amazon.com/Casio-GD350-1B-Shock-Black-Watch/dp/B00BU6RUU6

Edit: color options: https://www.amazon.com/Casio-G-Shock-GD350-8-Resin-Sport/dp/B00BU6TXEC

Up for sale is the Casio GD350-1B. Another watch that didn't make the cut. It has been a great daily beater and the negative display is actually really easy to read. Asking SOLD $55 PP and shipping included. Strongly prefer a ConUs sale and no trades at this time. Please feel free to ask any questions you may have and thanks for looking!

There are a lot of products out there. One way to research is to use Amazon and then look at "People who looked at this also looked at...". Also search through reviews and other forums. Here's some of my findings (I have no relationship or financial interest in any of this):

I'm going to start with what I think might be a great watch. Casio Vibration Alert Fishing or Hunting Watch About $50. I do not know if that link is a reputable seller! I'm guessing that Casio cares enough about their hunting/fishing watch owners that this watch is going to be sturdy. While it's focused on fishing, it's really amazing how many features this has. You can store 40 "time memos" which are supposed to represent "good fishing" or "I caught a fish" but one could use that to track events, such as completing a task each day. How about a time memo means "I took a pill"? and other watches of similar cost or more don't have the same comes with a whole bunch of neat features, including vibrating alarm (not sure if it can be reset)

This might even be better. Casio Men's GD350-1B G Shock Black Watch $89. It's a vibrating watch and according to one user, it's very easy to set and then repeat at the end. Very good reviews mostly 4 and 5 star.

The TimeTimer reviews indicate the product is good but may have serious quality issues and they break down. They have a watch too, I don't know how good it is. They also have an app for Android and iOS.

The WatchMinder2 has mixed reviews. Some people really like it. But it's very difficult to program.

The WobL seems to have some very good reviews and is $35. This link also includes many other products under the "Customers also shopped for..."

TIMEX Men's T498519J Rugged Digital CAT (Chrono/Alarm/Timer) Vibration Alarm Watch $31.85. Just one of many Timex vibration watches I guess. It has a countdown timer that you can reset and 3 daily reminders.


Casio Men's W-735H-8A2VCF Vibration Alarm Digital Watch. $34 I guess Casio has some vibration watches too. I might look at their features later.


Here's an interesting product:

I've agonized about posting this because I feel it's wrong somehow...which is absurb because it's an opinion...but
Casio Oceanus ~$580
Orient M-Force Delta ~$320
G-Shock ~$100

idk...I'm going to antagonize myself over this one for awhile.

edit: formatting