These MasonMate Loose Bolt Shield Anchors have the following specifications: Size: M12. Anchor Hole Size: 20mm. Shield Length: 75mm. Thread Diameter: 12mm. Fastens up to: 25mm. Bolt Length: 105mm. Min. Hole Depth: 85mm. Qty. Per Box: 20. The MasonMate Loose Bolt Shield Anchors are for use in most types of masonry or concrete. Zinc plated for increased durability. M12 x 25mm (20)