SPAX Hex Washer Head construction fasteners with HCR coating are intended for wood-to-wood connections in exterior structural applications when attaching treated lumber components. These fasteners are designed with a hex head conventional driver system along with a built in washer for applications requiring additional surface area under the head for superior pull-down force. Ideal for deck ledger attachment. Often used for blind, high torque applications where additional engagement of socket to screw head is needed.