This maintenance kit contains replacement parts for the rear swing arm suspension on compatible motorcycles.It includes components required to rebuild the swing arm assembly, specifically oil seals, needle roller bearings, and bushings.The kit is designed as a direct replacement for and restores the swing arm to its intended function. Type: Swing Arm Oil Seal Needle Roller Bearing Bushing Maintenance Kit Material: Steel and rubber Compatible With: KEWS K16, ZHONGSHEN NC250, NC450, MT250 NC250 Swing Arm Bushing Size: 17 mm x 22 mm x 55 mm NC250 Swing Arm Bearing Size: 22 mm x 30 mm x 23 mm NC250 Swing Arm Oil Seal Size: 25 mm x 35 mm x 5 mm NC450 Swing Arm Bushing Size: 17 mm x 22 mm x 43 mm NC450 Swing Arm Bearing Size: 22 mm x 30 mm x 16 mm Package Includes: 2 Swing Arm Bushings 4 Swing Arm Bearings 4 Swing Arm Oil Seals Fits models manufactured in China.Professional installation is recommended.Please verify dimensions of existing parts before purchase.Allow for minor measurement variance due to manual measurement. This is an aftermarket spare.Brand and model mentions do not imply manufacturer association.