Based on another review I was on the lookout for this. First ride with it I almost lost the light several times. On bumps it slides up on the fabric strap on my saddle bag. I stopped to check it several times on a 12mi ride. A couple of times, it had slid up so far it was barely hanging on. I was on a road bike. If I were mountain biking the light would have surely got thrown off. I've never had this issue with any other taillight attached to a saddle bag. This metal clip is very smooth. I suspect it's designed for clothing and not a saddle bag. For now, I'm going to use small rubber band around the bottom of the clip and light to secure it.