After waiting to gather up all the bits and pieces, it was time to get to modding. Tools & parts required: press, dust blower, case back remover, spring bar tool, domed sapphire crystal, tweezers, magnifying glass, rubber gloves; and of course, a cup of coffee.

The Casio Duro MDV106 comes with a flat mineral glass crystal, which is fine, looks good and is functional.

However, wouldn’t it be nicer with a domed sapphire? Sapphire is more scratch-resistant, and the dome will catch the light and give the watch a much better overall look.

How hard could it be to swap? In short: not very. By far the most difficult part, aside from keeping out dust and eliminating any smudges, was removing the crown from the movement, which requires pressing on a very specific little release tab that is not easy to find. A magnifying glass helps, but finding a good YouTube video demonstrating exactly where to press with the spring bar tool, is priceless.

Once the crown is removed, the movement and chapter ring pops out, and the crystal can be pressed out. This only requires choosing the correct diameter die on the press to ensure there’s space for the crystal to go when pressed, and “pop” out it comes.

Installing the new domed sapphire crystal is super-easy, it can be seated by hand so there’s little chance of misaligning it when pressing it back in. Going slowly, installation is reverse of removal, just flip the watch case over and carefully press it down into the case until it’s flush with the bezel insert.

I really like the new look, though I may be the only person that notices! Having never done this before, this was a low-risk and low-cost first attempt at watch crystal swapping. If I had destroyed the new crystal, or the watch movement, it’s not the end of the world. The Casio Duro is not rare nor expensive, but it is a great little watch. Now I’ve just made it a little bit better with a domed sapphire crystal (with anti-reflective undercoating), had some fun in the process, while learning something new.