SSP-G Variator Control Shims for GY6 125cc and 150cc Engines.Variator control shims can be installed between the drive faces to lengthen the boss if your variator does not open fully to allow maximum belt travel.For use with 24mm variator bosses only! Includes 3 shims, one 1mm thick and two .5mm thick. Please see our Warranty & Returns Policy. For Use With 24mm Variator BossIncludes One 1mm Shim and Two .5mm Shims