[Strong Breaking Strength] : Zipline pulley has a maximum breaking strength of 30KN (6700LBS), suitable for various outdoor applications such as rescues, swing seats, or backyard zipline setups. [Cable Diameter] : This tandem speed dual trolley is designed for ropes and cables; Maximum rope diameter: 13mm (0.5in); Maximum cable diameter: 12mm (0.36in). Fits 1/4, 5/16, 3/8, and 1/2 inch cables or ropes. This twin cart is lightweight and durable for outdoor use. [Material] : Zipline pulley features an aluminum and magnesium alloy shell with a stainless steel pulley. The double sheaves provide smooth rotation and efficient performance. [Efficient Working] : Two stainless steel discs with sealed stainless steel ball bearings prevent twisting, enhancing speed and efficiency. High-performance bearings support high-speed operation. This tandem pulley offers improved performance over single pulleys. Note: Due to differences in lighting and screen settings, the item's color may vary slightly from images. Slight dimensional variations may occur due to manual measurement.