.Lag Screw, 1/4 in, 3-1/2 in, Steel, Zinc Plated Hex Hex Drive, 100 PK A lag screw is similar to a wood screw, but generally is much larger with a hexagonal head.
.1/2"-13 x 12" Zinc Plated Grade 2 / A307 Steel Coarse Thread Carriage Bolts 25PK A carriage bolt has a domed or countersunk head, and the shank is topped by a short square section under the head.