12 pieces of M4 shackles with screw pins. Threaded pin for easy removal. The D-ring U-lock is made of 304 stainless steel, which is sturdy and durable, rust-proof, and unbreakable. Each shackle measures 21 x 24 mm. The inner dimensions of the handle are 8 x 14 mm. The thickness is 4 mm. They can support up to 80 kg of weight. Avoid bending loads, unstable loads, and overloading.