Big Brakes. Plain and simple, that's what the SSBC Extreme 4-piston brake upgrade kit is. Designed for larger 13'' and 14'' rotors and 17'' or larger wheels, this kit provides all the braking you could ever need. The SSBC Extreme 4-Piston series caliper uses four stainless steel pistons: either 38mm, 43mm or 48mm - depending on the application. Each caliper is constructed of lightweight aircraft quality aluminum to reduce unsprung weight and improve the ride quality. They are also clear anodized for an attractive look. The kit also includes stainless steel bleeder screws and uses stainless steel ARP bolts.