These MasonMate Hex Loose Bolt Sleeve Anchors have the following specifications: Size: M8 x 90mm. Max. Fixture Thickness: 55mm. Min Hole Depth: 35mm. Qty Per Box: 50. The MasonMate Hex Loose Bolt Sleeve Anchors are for use in most types of masonry or concrete. Zinc Plated for increased durability. M8 x 90mm (50)