CNC machined from 6061 aluminum to exact specifications. These aluminum rear axle spacers and bushings replace the stock steel pieces and weigh less than 1/3 of the heavy stock parts. An easy way to trim some weight off of the bike and look awesome too. Designed to fit the 74 250 mag but will also fit all models from 71 to 74 including the 1975 250 and 400 WR models. I also have these for the 75-77 models your choice. Six pieces in all.