Item s: -This greenhouse door wheels is fit for most greenhouses with sliding doors. Complete with bolts and nuts, convenient and pricatical to use. -Our greenhouse door wheels are made of nylon with stainless steel bearings, all screws and spacers also are stainless steel material, rust-proof and durable for long time use. -The diameter of nylon wheel is 29mm, inner diameter is 18mm; The screw is M6x18; The inner diameter of spacer is 6mm. Universal size to match most greenhouses with sliding doors. -Door wheel replacement kits have long service life and beautiful appearance, door wheels easy to move back and forth by sliding the door roller. -Package includes 4 pieces nylon wheels, 4 pieces M6x18 screws, 4 pieces hexagon nuts and 4 pieces 6mm spacers. Package: 4x Nylon wheels 4x M6x18 screws 4x Hexagon nuts 4x 6mm Spacers Item Specifications: Colour:White, silver Material:Nylon, stainless steel Diameter of wheel:29mm Inner Diameter:18mm Inner Diameter of Spacer:6mm Screw:M6x18