Optional 16, 20 or 24 piece tuner lug bolts 12mm x 1.50 threads lug bolts with tuner key. The bolt outer diameter is 3/4". The overall length is 1.88" (47.5mm) and the shank length is 0.95" (24mm). These lug bolts fit tuner style rims on VW, Audi,etc with 12mmx1.5 thread size studs. Installation key is included.