Aircraft Plastic Drywall Butterfly Anchor Kit (Set Of 10pcs) Butterfly Expansion Tube, Plastic Self Drilling Drywall Ribbed Anchors Assortment Kit Wall Installation (Gray) asus nereus backpack Madre de cacao car card organizer Madre de cacao Carfu auto mud guards jaos AC 3207 The split in the ribbed anchors expand on two opposing sides as you tighten the screw increased holding power anti rotation structure design of the expansion sleeve tighten the screw will not be followed in the drilling rotation The plastic material anchors are very durable and not easy to be broken drywall self drilling screws kit is made of metal which features high strength and offers good corrosion resistance in bad environment like high temperature cold weather and high humidity areas