TRP Hydraulic Tubing Coupler Kit Small Parts Small parts for TRP hydraulic disc brake systems are in stock and ready for you. The TRP Hydraulic Tubing Coupler Kit comes with a coupler, compression ferrules, brass inserts with an O-ring, and a hose retainer. It is available in 5. 0mm and 5. 5mm for TRP and Tektro brakes. Features Comes with a coupler, compression ferrules, brass Inserts with an O-ring, and a hose retainer Available in 5. 0mm and 5. 5mm for TRP and Tektro brakes | Trp | Hydraulic Tubing Coupler Kit Tl 1. 2, For For 5. 5Mm Hose