Hope Tech 4 V4 Disc Brake - Rear - Left Lever - 1720mm - Silver - Red eBay Alternately

Alternately

you would probably want something a bit less bulky for trail or XC type riding

Care additives for seals

that's not a figure of speech for toughness - they really are tested to Military Ballistic Impact Standards so you can be confident that no matter what is kicked up off the trail your eyes are perfectly protected

Hope Tech 4 V4 Disc Brake - Rear - Left Lever - 1720mm - Silver - Red eBay AlternatelyThe all new Tech 4 V4 builds on Hope's 25+ years experience designing and manufacturing hydraulic brake systems. The Tech 4 uses all new internal sealing for reduced friction and the pivot spins on roller bearings, allowing the spring rate to be reduced. The lower spring rate in turn gives a lighter lever action, reducing rider fatigue and keeping our legendary feel and modulation. The updated V4 caliper utilises hybrid style Stainless steel pistons