Stable Quality: Made of high-quality 304 stainless steel, this product offers excellent corrosion resistance, rust prevention, and oxidation resistance in various environments. Reverse Thread Design: Utilizing a left-hand (counter-clockwise) thread, the tightening direction is opposite to that of standard bolts. Ideal for applications where vibration or rotational forces would cause right-hand threaded components to loosen. Complete Size Range: Available in metric sizes from M4 to M20 to meet various load requirements. Smaller diameters (M4-M6) are included in sets of 2, while larger sizes (M8-M20) are included in sets of 1. Easy Installation: M4 stainless steel hook bolts can be easily and quickly attached to wood or masonry structures using suitable expansion bolts. Note: These are dedicated reverse thread fasteners. Before installation, ensure you have a compatible left-hand nut and understand the tightening direction. This product is not interchangeable with standard right-hand threaded components.