Expansion anchors are made of high quality materials for long lasting durability and dependability. Units are designed to anchor into block, concrete, or brick based materials. Threaded screw/bolt inserts into anchor, which expands against base material. Sizes range from 1/4" to 3/4". Package quantities range from 1 to 100. Finishes are Carbon Steel, Plain, Stainless Steel, Zinc, and Zinc Alloy. Dimensions vary per model.