Original German HK Rollers, Fit all HK Bolt Heads including German HK production 8mm rollers used. Surplus condition but in perfect working order. This is the standard sized roller installed on most new HK weapons. Fit all HK Bolt Heads including HK91/G3, HK93/33/53, HK94, MP5, SP89 all clones and the Cetme. Plus Size Rollers increase bolt gap. Minus sized rollers decrease bolt gap. HK93/33/53, HK94, MP5, SP89 all clones and the Cetme. ....................................................................................................................... THESE ARE THE STANDARD 8MM (.31496 IN DIA. ) ROLLERS.. THEY ARE USED SURPLUS.........AD IS FOR A SET OF 8 (EIGHT ROLLERS)