Gear Keeper RT5-2101 Micro Retractor (70 g / 2.5 oz)

Keeps gear perfectly. I have a few of these; most for scuba diving and can say they hold up for years under bad conditions. Never had one go down yet. They are expensive , but you get what you pay for with these.

Otherwise awesome, but the clip is just too tiny to clip to a jeans (Särmä tactical, but all jeans are alike there) belt loop quickly (which is the idea of a such clip). Cloth loops will not fit inside without much fussing, the clip won't close. You see it also on the illustrative picture here, cloth loop is squished, even though it is a woman's model with thinner loops. I did not notice it at first, but then discovered the sharp tongue of the clip had just pierced the jeans belt loop and stayed on that way. Obviously, not sustainable! I ended up having to thread keyrings into belt loops and clipping the micro-retractor to them. Some trousers have tiny extra strips of cloth with tiny metal triangles or rings front right, these are useful for this gadget. Or you could have a carabiner on your belt or trousers and clip the ring into it, use the gadget other way round, sort of.

Broke on the first day being used to hold my keychain...