3-piece design hardware for mounting 2003-2010 Rock Shox Ario*, Bar, MC, and Pearl rear shocks with 12mm eyelet dimensions *(not for newer "08+ models using 1/2" (12.7mm) hardware: Vivid, Monarch, 2010+ Ario) Sized by bolt diameter (M6 or M8) and frame mount-ID width (in mm) 2 hardware kits required per shock: 1 for each eyelet