Arborist-specific: The small and medium versions are now manufactured using Hot Forged Technology, combined with high quality materials and components. These blocks are rope friendly, durable and extremely robust. These features combined give maximum security and strength, when the block is rigged as part of an impact system. Apart from the aesthetically pleasing curves, the ISC impact pulley is designed to work (together with textiles) to absorb the huge forces which are created by the harsh dynamics of heavy Arborist work. The side plates are produced using the best quality hot forged Aluminium and the special manufacturing process allows these pulleys to offer a highly impressive strength to weight ratio. Features & Specs: MPN: RP050A1 Rope diameter range (mm)Max 16mm (15/8") Working Line Max 25mm (1") Topping Strop (WLL) Working Load Limit (kg)2000 (WLL) Working Load Limit (lbs)4400 Pulley wheel colour Orange Anchor wheel colour Red Wheel material Aluminium