reinforcing tire against punctures
hi, I've been to the bike shop today and inquired about that kevlar strip that is inserted between the tube and tire to reinforce it against punctures, well they didnt have that particular thing but they had some piece of hard rubber that suppose to do the same trick and then they went ahead and fixed it in the tire for me (for some added funds) , is it a common practice? since its just rubber and not kevlar is it going to give me any extra protection? cheers