Have used this on my 'standard' lens (12-40 pro) on EM-1 for two summer seasons now, touring, hiking, climbing, in California, Alaska, BC, Yukon, and parts of eastern Canada/USA. Have taken it off and put it on thousands of times. Never had a problem, though I often have to fiddle a little with it to convince myself it will stay on (admittedly on a UV or clear filter). I use a single-point strap to a long swiss arca plate mounted on the bottom of my camera, with the attachment point at the left end, so my lens hangs down pointing left instead of sticking out (better for hiking and climbing). So, the cap constantly rubs below my chest, and usually against the top of a fanny pack worn forward (because I always have a backpack), and occasionally it swings and makes contact lightly iwith rock in front of me when I'm climbing. The black anodizing has worn off around the edges because of this, but the cap has never come off the lens. It has never failed mechanically, nor do I see any obvious reason why it might. I think in comparison with many other caps on other lens brands that I have experienced, this is near the high end, not the middle or low end. Room for improvement would be to make it feel like it really clicks into place when it is on, but few lens caps achieve that, especially on filters. This lens cap does the job and has never let me down, even wet and dirty, and under conditions that are considerably more demanding than 'routine use'.