These MasonMate Loose Bolt Shield Anchors have the following specifications: Size: M16. Anchor Hole Size: 25mm. Shield Length: 115mm. Thread Diameter: 16mm. Fastens up to: 30mm. Bolt Length: 150mm. Min. Hole Depth: 125mm. Qty. Per Box: 5. The MasonMate Loose Bolt Shield Anchors are for use in most types of masonry or concrete. Zinc plated for increased durability.