This is pack of 15 Ultimate Racing differential shims. These are the small shims used to shim the side to side position of the front and rear differentials within the bulkheads, to adjust the backlash between the differential crown gears and the small pinion gear connecting the center drive shaft.
The pack includes 3 different thicknesses:
16x13x0.15mm. (x5)
16x13x0.2mm. (x5)
16x13x0.3mm. (x5)