Had mine about 3 months, the yellow ones. yesterday i tested the effectivness of them and i can say that they most certainly do work, doing a small downhill switchback managed to fall off and strike my knee on a large pointy rock hard enough to cause a graze behind the knee pad, after a few minutes hopping about the pain stopped and we contuined onward, well today apart from the small graze and a slight bruise there is no other pain or mark, if i was not wearing the pad it would of been a A and E job as the force of the fall twisted my bars off centre and 1 brake lever upwards whilst removing some metal from caliper, They do not slip down nor get too hot and keep the knees warm in cold coditions, i bought mine a large size after measuring the knee and the fit is good