Allows definitive measurement of brake pads to determine remaining life can attain a brake pad measurement without removal of any parts quick reference of brake pad condition via color code scale speed up your inspection processincrease customer satisfaction by having actual measurement to determine if service is required speed up your inspection process. the 6596 allows for a definitive measurement of brake pads to determine remaining life. unique design allows for measurement on the vehicle without the removal of any components in most cases (wheel assembly or brake caliper). quick reference of brake pad condition via color code scale. attain measurement without removing any parts from the vehicle.barrel meaurement (8 mm or more) quick reference color (green) brake pad condition (no replacement necessary)barrel meaurement (3 mm to 8 mm) quick reference color (yellow) brake pad condition (suggest replacement soon)barrel meaurement (0 mm to 3 mm) quick reference color (red) brake pad condition (recommend replacement)