your best bet is to try a bike shop. You CANT just buy any compression ring, however, because they have to match your specific headset. With a 1 1/8th headset you can mismatch spacers, no problem. but the compression ring, cups, and crown race are all going to be specific to your specific headset and will not be compatible with another 1/18th headset. unless ofcourse it happens to be the same model and brand..