0.470" x 4" Strong-Drive SDHR Combo-Head Screw - Zinc, Pkg 25The Simpson Strong Tie Strong Drive SDHR Combo Head Screw is made for serious wood projects like cross laminated timber (CLT), mass timber, and other big framing jobs. The unique combo head design gives you flexibility, with a choice to drive it with either a hex bit or a T40 6 lobe bit. A knurled shank helps lock the screw in place, and the sharp Type 17 point starts fast, reduces driving torque, and often eliminates the need for predrilling.