For shifter applications only. The 5mm SIS housing uses our metal cable ferrules. The smaller/lighter 4mm housing uses our 4mm plastic ferrules. Index shifting gear housing is identified by the tiny wires running the length of the housing. These are there to ensure the housing doesn't compress against the gear cable when the shift lever is pulled. It's imperative to keep ferrules on the ends of this housing. It's also extremely important to use a gear ferrule only and not a brake ferrule. THIS PRODUCT IS SOLD BY THE FOOT.