6mm Bore Bearing - 21mm Round Nylon Pulley U-Groove Track Roller 6x21x7mm

6mm Bore Nylon U-Groove Pulley with
✨ Built-in Track Roller Bearing - 6x21x7mm

This is a single U-groove nylon pulley with a 6mm inner diameter and a built-in steel ball bearing. Commonly used in sliding doors, 3D printers, track systems, and automation setups where smooth guided motion is key.

🟢 Size: 6mm x 21mm x 7mm
🟢 Inner diameter (bore): 6mm
🟢 Outer diameter: 21mm
🟢 Tire width: 7mm
🟢 Pulley material: White nylon
🟢 Integrated steel ball bearing
🟢 Style: U-groove round track
🟢 Quantity: 1 bearing