EXTREME XTC Climate Proof Screws. Designed by engineers and building professionals for superior durability, strength and performance! Outperforms most leading brands of structural exterior screws for a fraction of the cost. Length: 3-1/8". Extra Tough High Strength Carbon Steel Alloy. Ruspert 1500 Triple Coated. ASTM B117 Tested - 1500 HRS Salt Spray Verified. Class 4 Fastener suitable for Marine Environments. Type 17 Self-Drilling Tip w/ chip groove. Knurled shoulder draws materials tight. Serrated threads lower driving torque. Suitable for use in all treated and untreated materials. Suitable for use in ACQ treated materials. T-25 drive - Free Bit Included. ASTM D1761 Shear Values: #10=1030 lbf. ASTM F606 Single Shear: 1983 lbf. Available in 5 lb reclosable plastic bins