Our Stainless Steel Trailing Arm Alignment Kit is a direct replacement for GM parts. Unlike GM adjustment shims, these parts won't rust, making rear end alignment much, much easier. This kit costs less than the price of buying the shims separately and includes (enough for both arms): 24 stainless steel alignment shims (in 4 sizes), grade 5 pivot bolts, cotter pins, castle nuts and 4-1/2" long cotter pins. Instructions included.