These brakes came from an early 2010s mountain bike that I'm parting out. The front works great and stopped the bike perfectly when it was assembled. The rear was working, but the lever needed to be compressed all the way to get it to stop. It seems that there's an air bubble in the system and it needs to be bled. I work with mostly vintage stuff and don't like messing with hydraulics. Can be used as is, in a pinch, but highly recommend bleeding the rear brake. Listed as "for parts/not working" for this reason.