I bought the same ones but with a hole predrilled so I could attach it to my BCD. They're cheap and easily replaceable. You want a glass lens, not plastic. I recommend detaching it during surface intervals if you have dive staff help change out your gear or clean your gear at the end of the day. I left mine attached and didn't realize the glass was missing until mid-dive. I couldn't figure out what was going on with my eyes, noticed there was no glass, motioned to my buddy, stuck my hand through the hole and wiggled my hand, and she nearly spit out her regulator laughing.
