14 Gauge. ZMAX G185 Zinc Galvanized. Install the DTT2Z to the deck joist or blocking using Simpson Strong-Tie screws (SDS) included. For guardrail-post reinforcement, install a 1/2 diameter machine bolt or threaded rod through the post and into the seat of the DTT2Z. For deck-to-house attachment, use 1/2 diameter threaded rod to connect the two DTT2Zs. A standard cut washer (included) must be installed between the nut and the seat of the DTT2Z for all installations. Simpson Strong-Tie screws (SDS) install best with a low-speed, high-torque drill with a hex-head driver. Includes 1 with washer and screws.