Plastic spacers are isolation devices made of polymer plastic materials, typically installed between two components that need separation or adjustment of clearance (such as bearings, bushings, and moving parts). By providing an isolation layer, they reduce direct contact between components, thereby reducing friction, wear, and vibration. In fitness equipment, plastic spacers are mainly used at joint connections of strength training machines, between adjusting screws and supports, and in sliding guides, effectively improving the smoothness of equipment movement and extending its service life.