Gate Helper Wheel Frame is Galvanized Steel to Prevent Red Rust. Gate Wheel is Well Constructed This Size Helper Wheel is Used on Projects Where Gate Frames are from 1-3/8" - 1-7/8" OD Pipe Use this Support Wheel with 1-3/8" - 1-7/8" Outside Diameter Pipe Gate Frames. Easy Installation The 6" Wheel Provides Smoother Operation than Smaller Wheel Designs. Easy to Install w/Included Bolt Gate Helper Wheel Supports Gates to Prevent the Gate from Dragging on the Ground. Gate Helper Wheel has 6" wheel, for Chain link Fence Gate is for support Large Heavy Swing gates, to keep from sagging and staying levelled. supporting the gate stay level when opening and closing.