●Material: Made of high quality nylon, prevents noise, smooth and quiet. ●Range of Use: Pulley is small and light, good for Wire Amateur Radio Loop Antennas, DIY School Pulley Frame Project, make a small pulley systems to help people learn about pulley, lift some small goods. ●Load Bearing Capacity: The maximum load bearing capacity of the pulley is 20kg, and the safe bearing capacity is 5kg. ●4mm: These small pulley is good for 4mm rope. ●item quantity: 20 pcs pulley.