MATERIAL:6061-T6 ALLOY, FULL CNCTHICKNESS:6.5MM (SPROCKET), 10MM (GUARD)SIZE:25TSPECIAL FEATURES: SUPER TOUGH LOW FRICTION 10MM NYLON/FIBREGLASS GUARD 5X BOLT INTERFACE FOR INCREASED DURABILITY 23.8MM BORE HOLE (WITHOUT ADAPTER ADDED) INCL. 3 ADAPTERS TO FIT 19MM AND 22MM SPINDLESWEIGHT:157G (5.55OZ)COLORS:BLACK/OILSLICK