Application: Carriage Bolts are made of 304 stainless steel 18-8, corrosion resistance, do not worry about rust.These are perfect for use near salt water, fresh water and other wood related projects. Dimension: Bolt Length: 4-1/10" and 2-3/5" Material: 18-8 (304) Stainless Steel Including: 4 Pcs 1/4” x 2-3/5” bolts,4 Pcs 1/4” x 4-1/10″ bolts, 8 PCS hex nuts ,8 PCS Flat washers If you encounter any problems, please contact us, we will quickly solve it for you!