These MasonMate Hex Loose Bolt Sleeve Anchors have the following specifications: Size: M10 x 55mm. Max. Fixture Thickness: 15mm. Min Hole Depth: 40mm. 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. M10 x 55mm (50)