Description: 【Premium Quality】: The Petal Rivets Nut Jack Nuts Car Metal Screw are made of carbon steel, not easy to rust, strong structure and maximum durability. 【Expansion Design】: The anchors expand on two opposing sides as you tighten the screw, increasing holding power. 【Easy to Use】: petal screwAnchors Screws with the deep cross groove are not easy to slip when screwing, saving your energy. Combination head on screw has the ability to receive slot and cross slot screwdriver. 【Package】: Including 25pcs Petal Rivets Nut Jack Nuts, Car Metal Screw for Hollow Wall Iron Skin Petal Nut Expansion Lantern. 【Wide Application】: Petal Rivets NutWidely used for gypsum board, drywall, light brick wallboard, etc. Work great on hanging all kinds of items on your home decor, such as Curtain installation, lamp installation, object fixing, picture frames, wall lamps, curtains, clocks, etc. Specification: Material: Q235 carbon steel Size Chart: Model: 4x20 Casing outer diameter: 8mm Casing length: 16mm Casing inner diameter: 4mm Nominal length: 20mm Model: 4x25 Casing outer diameter: 8mm Casing length: 20mm Casing inner diameter: 4mm Nominal length: 25mm Model: 5x25 Casing outer diameter: 10mm Casing length: 20mm Casing inner diameter: 5mm Nominal length: 25mm Model: 6x25 Casing outer diameter: 12mm Casing length: 20mm Casing inner diameter: 6mm Nominal length: 25mm Model: 8x30 Casing outer diameter: 15mm Casing length: 21mm Casing inner diameter: 8mm Nominal length: 30mm Package Includes: 25 Pieces of Petal Expansion Nuts (with screws)(4 Pack) Note: Please allow slightly errors due to manual measurement and different monitors.