Key Features Specifically designed to replace nails in certain Simpson Strong-Tie connectors and is the only screw approved for that application. The #9 and #10 SD screws replace 10d and 16d nails, respectively. Tested and approved for use in many of our most popular connectors for both interior and exterior applications. Ideal for use in connector applications where more control is desired or using a hammer is inconvenient. 1/4" hex head with 0.37"-dia. integrated washer is stamped with the Simpson Strong-Tie "?" sign and the fastener size for easy identification after installation. Shank is specifically designed to match the fastener holes in Simpson Strong-Tie connectors. Optimized heat treating for ductility and strength. The single-fastener load capacity of the SD9 exceeds the capacity of a 10d common nail, while the single-fastener load capacity of the SD10 exceeds that of the 16d common nail. Hex driver included.