install them, the**03 portion of the id # tells you its for a triple and has an extra detent on the left side to trim the large ring. so you get small ring, position 1 on middle, position 2 on middle, poition 1 on large, and position 2 on large. why they didnt do this on 105 is a mystery to me. however I do know that 105 will work with a double or triple. In short if you have a 10 speed, and a triple crank, 6603 is what you need.