Plastic Ribbed Anchor Kit 20 EA #4-6 x 7/8 in 15 EA Anchors #8-10 x 1 in 10 EA #10-12 x 1-1/4 in 20 EA Anchors & Screws. These ribbed plastic anchors are intended for light duty anchor applications. The ribs prevent the anchor from turning in the hole during installation and expand as the screw is tightened.