sewage and atmospheric conditions

8 x 2 1/2 Simpson Truss-Head Wood Screws - Square Drive 305 SS - Box (100)

3/4 x 5 Hex Lag Screw Hot Dipped Galvanized

1 1/4-7 x 4 1/2 Socket Cap Screw Alloy

12 x 2 1/2 Simpson Flat-Head Self-Drilling Screw w/ Wings - Square Drive 410 SS - Carton (1800) 10-32 Socket Cap Screws Alloy sewage and atmospheric conditions12 x 2 1 2 Simpson Flat Head Self Drilling Screw w Wings Square Drive 410 SS Carton (1800) . Fasten wood, plywood and fiber cement to heavier steel up to . 209" thick #3 square drive Machine screw thread, threaded full length 2 1 2" length for 2 x 4 wood header; 2" length for 1" and 3 4" boards Flat countersunk head with self countersinking nibs Shank slot enhances thread formation in steel and removes exhaust Wings above drill point provide clearance