1/4-20 x 5 1/2 Carriage Bolt Galvanized 1 1/4-7 and the 4 1/2 refers

and the 4 1/2 refers to the length of the bolt

This 5/16-18 x 3 1/2 inch Grade 5 fully threaded carriage bolt is made of steel and has a zinc finish for corrosion resistance

5/16-18 x 4 1/2 Hex Cap Screw Grade 5 Zinc is a high-quality fastener designed for use in a variety of applications

This 1/2-13 x 1 1/4 inch fully threaded carriage bolt is made of steel and has a zinc finish for corrosion resistance

1/4-20 x 5 1/2 Carriage Bolt Galvanized 1 1/4-7 and the 4 1/2 refersThis 1 4 20 x 5 1 2 inch carriage bolt is made of steel and has a galvanized finish for corrosion resistance. It has a square head and a fully threaded body. Carriage bolts are typically used to fasten wood to wood or metal to wood. The square head prevents the bolt from turning when it is tightened, and the fully threaded body provides a strong hold. This bolt is suitable for both indoor and outdoor use.