Anchor Shackles from Chicago Hardware are forged, then hot dipped galvanized for improved corrosion resistance. Screw pin type shackles meet federal specifications. When tested, all shackles are pulled at uniform rate of speed in a direct tension. All loads are based on a safety factor of 6 to 1. Size, maximum working load and trademark are marked in raised lettering at top of shackle eye. Manufacturer notes that any deviations such as angular lifts, shock loads or modification of basic forging will result in drastically reduced maximum loads.