All Pulleys in our latest Heavy-duty Prussik range have tamper-proof Rivets,in compliance with CE EN12278 (2007) & NFPA (1983)*These Pulleys are available in Aluminium or Stainless Steel,with Bushings or Roller Bearings. Bushings are ideal for high loads at low speeds and Roller Bearings are ideal for low loads at high speeds. Pulleys in the new Prussik range have fully loadrated Beckets,which are large enough to allow a Karabiner to rotate fully.