A carriage bolt has a domed or countersunk head, and the shank is topped by a short square section under the head. The square section grips into the part being fixed (typically wood), preventing the bolt from turning when the nut is tightened.

Diameter: 1/4"
Length: 5-1/2"
Material: Steel
Finish: Zinc
Head Style: Carriage
Thread Size: 20 (Coarse)
Thread Length: Full
Hardness: Grade 2 / A307
Type: Carriage Bolt
Square-Depth: 5/32"

Diameter: 5/8"
Length: 3-1/2"
Material: Steel
Finish: Zinc
Head Style: Carriage
Thread Size: 11 (Coarse)
Thread Length: Full
Hardness: Grade 2 / A307
Type: Carriage Bolt
Square-Depth: 11/32"

Diameter: 1/2"
Length: 3-1/2"
Material: Steel
Finish: Zinc
Head Style: Carriage
Thread Size: 13 (Coarse)
Thread Length: Full
Hardness: Grade 2 / A307
Type: Carriage Bolt
Square-Depth: 9/32"

Diameter: 1/4"
Length: 6"
Material: Steel
Finish: Zinc
Head Style: Carriage
Thread Size: 20 (Coarse)
Thread Length: Full
Hardness: Grade 2 / A307
Type: Carriage Bolt
Square-Depth: 5/32"