Review on RuenTech Case Cover Compatible With Garmin Fenix 6X/6X Pro/Fenix 6X Sapphire Case Protector TPU Protective Case Frame For Fenix 6X GPS Watch (Pink/Blue/Purple/Black/Clear) by Aaron Wagner

It did a great job protecting my Fenix 6X Pro and as you can see from the picture it has sustained "war wounds" from damage when I hit my watch against objects hit while I was doing my own thing. (For reference, the 6X is a BIG watch and thick, so you'll run into it quite often). It fits well and is probably as thin as possible to keep its shape. I would recommend taking it off and cleaning underneath at least once a week or after it gets wet; This causes dirt and water to collect between the case and the watch, which can affect the case and finish of the watch.