Axle Collars by PKT. Help to prevent lateral slip of rear axles in all karts. Each collar is notched for clearance over axle keyways. Black anodized finish for durability and long service life. Integrated raised shoulder to mate solidly against axle bearing face. Choose from the following collar sizes (Inner Diameter) to suit your application: 30mm: For Cadet kart applications, and a handful of Kid Karts that use the larger 30mm axle. 40mm: For 40mm axle applications, many American-made chassis such as Margay models, some 4-stroke specific karts. 50mm: For 50mm axle applications, most 'full-size' karts utilize 50mm axles. Each collar is sold individually, and includes clamping bolts and washers, but no additional hardware.