Durable nylon construction built to withstand wear across many applications. Quiet and smooth operation with integrated lubrication to minimize noise and keep your setup running cleanly. Innovative U-shaped design reduces friction for improved performance in a variety of projects. 4-pack provides excellent value and easily covers multiple project needs. Key specs - Material: nylon - Type: U-shaped pulleys - Pack size: 4 pieces - Compatibility: designed for belt drive systems that use U-shaped pulleys (verify fit with your belt width and groove requirements) Use scenarios - In DIY robotics or hobby machines where multiple belt-driven joints require reliable, quiet idlers. - In small-scale belt-driven equipment such as 3D printers or other hobby machinery to improve belt guidance and reduce wear. - In educational kits or workshop projects that require multiple pulleys for demonstrations, experiments, or prototype builds.