Lag Bolt Screw Hot Dipped Galvanized A207 Alloy Steel 1/4 x 2-1/2 Qty 1000. Lag screws, also commonly reffered to as lag bolts, are heavy duty wood fasteners. Lag screws require a pilot hole pre drilled before installation and to be driven in with a ratchet due to their size. The minimum thread length shall be equal to one-half the screw length plus 1/2?Or 6, whichever is less. Above Mentioned is a General reference, If exact thread length is needed please inquire. Hex Head Width Flat to Flat : 7/16" (0.4275"). Body Diameter : 1/4" (0.250"). Length Measured Under Head : 2-1/2. Quantity of Fasteners In Package1000. Material : Galvanized A207 Alloy Steel. Tracking is provided on ALL Orders. UPS Next Day Air is available, Please inquire for pricing. For YOU, we constantly strive to find ways to improve our performance.