Originally Posted by Ingleside

I believe the longer one on the right is used on frames where the housing stop on the chainstay is just a small loop where the narrower part fits through. Older frames had this style of housing stop on the chainstay before the full length ones we see today appeared on frames.

I am not too familiar with Campy as to whether of not you install the housing ferrules (not grubs) on the side of the housing that enters the shifter or just leave the housing naked. The manual or someone else on here will know the answer.