1.[ Strong Breaking Strength ] : zipline pulley has a maximum breaking strength of 30KN 6700LBS, so it can keep you in most outdoor applications, such as rescues, swing seats or backyard zipline settings, etc. 2.[ Cable Diameter ] : This tandem speed dual trolley is specially designed for ropes and cables; Maximum rope diameter: 13mm/0.5in; Maximum cable diameter: 12mm/0.36in. Fits 1/4 5/16 3/8 1/2 inch cable or rope. This twin cart is extremely lightweight and durable enough for your outdoor adventures. 3.[ Material ] : zip line pulley is made of aluminum and magnesium alloy shell and stainless steel pulley. The double sheaves of pulley provide great smooth rotation and efficient performance. 4.[ Efficient Working ] : Two stainless steel discs with sealed stainless steel ball bearings prevent twisting for increased speed, efficiency and . Feature efficient bearings for high-speed adventure.This tandem pulley works better than a single pulley. Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2.All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances. 3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours Hope you have a pleasant shopping experience!