Product Info Catalog Hardware Builders Hardware Springs Extension Springs, 5/8-In. OD x 3-1/4-In., 2-Pack Extension Springs, 5/8-In. OD x 3-1/4-In., 2-Pack Request a Quote UPC: 38594001813 SKU: 681296 Model Number: C-181 2 Pack, 5/8" OD, Extension Spring, 3-1/4" Length, .072" Wire Diameter, 2.01" Maximum Deflection, 19.1 LB Maximum Safe Load, Polybag.