? SMOOTH OPERATION: Internal lubrication grease, smooth operation, good mute effect.
? U-SHAPE GROOVE DESIGN: Smooth surface reduces friction.
? APPLICATION: Widely used in doors and windows to track and drive mechanical equipment.
? MATERIAL: Made of high quality material, these pulleys are durable, sturdy and wearable.
? 4 PIECES IN ONE SET: There are total 4 pieces of pulleys in one set that you many use for many projects.