6PA. 6PB. 7NZ. 7PA. 7PB. Sierra Hybrid; Code 6NZ. Sierra Hybrid; Code 7NZ. Silverado. A component (mounted in the center of the spring) which cushions the spring as it is compressed. Jounce Bumper. Suspension Strut Bumper. Suspension Strut. Coil Spring Damper. Dust cover. Jounce. Stop.