Why is Casio’s basic metal cased diver’s watch, the MDV-106, a best seller? Despite having a japanese made quartz movement, it doesn’t have a backlight or any extra functions. It just tells the time and the date. You set it with a screw down crown. Commenters tell me to pick one up. So I got a Casio Duro, (or a Marlin as they’re sometimes called) to see what makes it so popular.

It’s a Big Boy!

The first good thing I noticed extricating the Casio Duro MDV-106 from its box is that it has size both in the case and in the factory resin band. It has large proportions, unlike other Casio best sellers such as the F91W.

The band, intended for diving usage, is longer to fit over a wet suit. This works well for big wristers who’d like a longer band than Casio typically makes even if they don’t don a wetsuit. On my 8 1/2″ wrist, I got it to fit on the last notch and could snug it up to the second to last notch to fit tightly.

If you are a big wrister profundo and need more strap length, the huge advantage to the Casio MDV-106 is that it has standard lugs since its case is a normal dive watch shape. You can get an extended length band and swap it out, unlike other Casios which have narrowed and nested lugs.

It’s a Basic Watch

For those of you who want to backlash against smart watch connectivity so hard you get whiplash, the Casio Duro is an analog watch whose hands and date wheel are set with a screw down crown. Talk about boomer technology! Wearing the MDV-106 connects you with the old heads who reminisce about the first time they saw a digital watch.

Analog is a good way to tell time. After you get used to it, you may actually prefer it to digital. So if you’re new to analog watch reading, the Casio MDV-106 is a good way to dip your toe since it doesn’t cost as much as a luxury mechanical.

The Price

The cost of the Casio MDV-106 is one reason it sells so well. The scale at which Casio produces these units allows sellers to offer discounts. Sales abound for the Duro. Shop around until you find a good price. The retail price listed at Casio.com at the time of writing is $84.95. I got mine on Amazon and I paid a even less.

This is not an El Cheapo Casio since it’s closer to the $100 mark, but it’s an all metal case analog diver’s watch with a made in Japan movement. That makes it a tremendous value. I think it looks terrific and does the job of telling the time as well as a much more expensive luxury watch.

Video Summary

Thank to Google’s Gemini AI, you can read a summary of my chaotic Unboxing video. Here is what it generated after watching it on YouTube:

Casio Duro (MDV-106) Review: The $85 Marlin Diver Putting Luxury Beaters to Shame

Widely regarded as the undisputed king of budget dive watches, the Casio Duro (MDV-106)—often called the “Marlin” after the iconic sailfish engraved on the dial and case back—has earned a near-mythic reputation among watch collectors and tradesmen alike. In this unboxing and first-look overview, Jim Kinkade inspects the legendary 200-meter diver,evaluating its true solid-metal case construction, bezel action, screw-down crown mechanics, factory strap fitment on an 8.5-inch wrist, and how its exposed crystal stacks up against heavy-duty G-Shocks.

Solid Metal Construction: “No Cap” Stainless Steel

Many modern affordably priced Casios achieve their rugged aesthetic by snapping a decorative stamped-metal bezel over an inner resin case. The Casio Duro takes the traditional, honest horological approach:

• Full Stainless Steel Case: The Duro features a hefty, monolithic stainless steel case with polished flanks and brushed lug tops—giving it genuine presence and density in hand.
• Screw-Down Case Back with Marlin Insignia: Unlike four-screw resin case backs, the MDV-106 utilizes a heavy threaded screw-in steel back rated for a true 200 meters (20 BAR) of water resistance, proudly stamped with the classic jumping Marlin logo and housing a reliable Japanese quartz movement (cased in China).
• Mass & Inertia Realities: Solid steel brings undeniable durability against crushing and high hydrostatic pressure,but Jim notes that metal carries significantly more mass and inertia during direct tabletop impacts compared to hollow, shock-absorbing resin G-Shock modules.

Crown & Dial Mechanics: Simple Analog Reliability

In an era where digital watches and Bluetooth modules automatically alter time zones without permission, the Duro returns to pure mechanical simplicity:

• Threaded Screw-Down Crown: Protected by robust case crown guards, the screw-down crown prevents water ingress and protects the internal stem from snagging. Jim emphasizes the critical shop rule: always double-check that your crown is fully screwed down before getting near liquids.
• Hacking Seconds Hand: Pulling the crown to the second position stops (hacks) the seconds hand at 12 o’clock,allowing precise synchronization against an atomic clock or Multiband 6 reference. Jim syncs the Duro to the second using the newly released GW-BX5600 MIP square.
• Clean Date Complication: Features a dedicated 3 o’clock date window operated via the crown’s first click position.
• Dial Legibility & Seconds Alignment: The high-contrast black dial features bold, luminescent indices, an arrow-tipped red seconds hand that hits its chapter ring minute tick marks cleanly, and a lumed pip at the 12 o’clock bezel position.

Unidirectional 120-Click Bezel

• Anti-Reverse Rotating Bezel: Engineered strictly to dive standards, the coin-edge bezel rotates counterclockwise with crisp, tactile clicks.
• Elapsed-Time Tracking: Setting the 12 o’clock triangle to match the minute hand provides an instant, foolproof mechanical timer for shifts, laundry, or lunch breaks without fiddling through digital submenus.

Factory Resin Band Fitment & Standard Lug Swapability

The most common internet critique of the MDV-106 centers on its factory resin band:

• The Big-Wrist Verdict: On an 8.5-inch wrist, the stock accordion-style resin strap fastens on the second-to-last notch, providing a secure fit while tucking into the keeper.
• Ratcheting “Keeper Keepers”: The inner spine of the strap features molded ridges that lock the rubber keeper firmly in place, stopping the strap tail from sliding free during movement.
• The Standard Lug Advantage: Unlike G-Shock squares and Master of G models that utilize proprietary recessed or nested lugs, the Duro uses standard straight spring-bar lugs. Wearers can instantly swap out the factory resin for 22mm NATO webbing, heavy nylon canvas, or aftermarket stainless steel bracelets in seconds.

Exposed Flat Crystal vs. G-Shock Crenellations

• Crystal Exposure: Unlike the Mudman GW-9500 or NASA GW-6900, which feature raised, crenellated resin bezels designed to deflect scrapes and drain mud, the Duro’s flat mineral glass sits flush and exposed to potential abrasive contact.
• No Sapphire at $50: While high-end tool watches like the Citizen Promaster Land U822 withstand engine bay scrape tests thanks to sapphire crystals, the Duro relies on budget mineral glass. However, at its sub-$60 price point,surface wear and scratches are easily accepted as honest work patina.
• A Meeting with Destiny: Jim teases that the Duro will soon face the ultimate workshop rite of passage: a high-impact durability showdown with the Watch Bopper 5000.

The Verdict

The Casio Duro MDV-106 earned its cult status for good reason. For the price of a couple of oil filters, it delivers a legitimate 200m diver with a rock-solid Japanese quartz heart, an all-steel screw-back case, and universal strap compatibility. If you want an honest, handsome work watch that requires zero app connectivity and looks right at home whether turning wrenches or diving underwater, the Duro is practically impossible to beat.

Conclusion

The Casio Duro MDV-106 gives you a lot of watch for the money! Stay tuned as I tough test it and subject it to the use and abuse of all my watches. We’ll see how it stacks up. Buy the Casio “Marlin” by clicking here!