General description Used as an electric door top wheel, this M12 48 x 50 mm PP Steel Roller Bearing Guide Wheel is suitable for various applications including placement door nylon flange wheels, iron door wheels, electric door wheel guides, track wheels, and pulleys. Made of durable PP steel, it features two 6201ZZ bearings, making it a great replacement for old or damaged bearings. Technical specifications Dimensions: 48 x 50 mm Material: PP steel Bearing type: 6201ZZ Pack size: 2