I have been looking for a tripod ring for my Canon EF 100mm F 2.8 USM macro lens forever. I’m not talking about the L version of this lens. They apparently do not exist. I am here to say that this particular tripod ring works perfectly on that lens. And at an unbelievable price. I was just about to try and find somebody to 3D print me one. Until I came across this. The 70.5 mm diameter of this ring is the exact same size as my lens. So if you are looking for one search no more this is it!