The J's Racing 6 pot caliper is made out of forged aluminum. This is to dissipate heat under extreme braking tempurature, to reduce brake fade when under abuse. To keep unsprung rate down to a minimum, forged aluminum is used as the material for this caliper. This kit includes 323mm 2pcs rotor x 2, caliper with mounting brackets x 2 and Front brakeline x 2 pcs. *Additional spacers are required for clearance from caliper to wheel.