This unit comes in three sizes and it will be up to you to tell us what make and model your car and engine are. The dimensions and screw size are as follows:
Size 1: 65 mm diameter with a 3/4-16UNF screw size
Size 2: 65 mm diameter with a M20-P1.5 screw size
Size 3: 75 mm diameter with a 3/4-16UNF screw size
Get these and all your other Sard goods from RHDJapan faster and for a fraction of the MSRP.