Our own design, and I/Grant have used these for more than twenty years, and have never been hit in the ankle. This reflector has by far the most reflective surface of any ankle reflector. It adjusts to wrap over thick or thin pants, whatever you like. There's lots of velcro, so once you put it on, it'll stay. Wear one on the left for cars to see; on the right to keep your slacks out of the greasey chain. Whatever you like, but as ankle reflectors go, this is the best one out there. White or lime Reflexite. The same stuff that the Triangle is made of. Now sewn to a strip of black felt for reinforcement.