The Hope Pro 4 Hubs ?have proven their reputation for bulletproof quality, time and time again. The sealed stainless steel cartridge bearings throughout the hub offer unparalleled support. The hub shell is machined from forged T6 Aluminium billet. Hope Pro 4 Hubs Features Standard 6 bolt disc fitting Unsurpassed reliability Conversions available for QR, 9mm, 12mm, 15mm, 20mm and Boost Larger diameter spoke flange, to build stiffer wheels Weight QR - 187g, 9mm - 184g, 15mm - 181g, 20mm - 173g