When we are talking about multi-piston brake calipers, some are directional and some are not. One trick brake caliper manufactures use to help get better performance is to use staggered caliper piston sizes. This means if you have a 4 piston caliper, 2 pistons will be slightly smaller in diameter than the other 2. This is done to help minimize tapered brake pad wear. Because of the different size pistons, these calipers are directional. Therefore you want to ensure that as the rotor rotates through the brake caliper it is passing the smaller diameter pistons first then the larger pistons last. See diagram below.If all pistons are the same size, then the caliper is not directional. Please contact Gorsuch Performance Solutions to learn how to get more out of your brake system!