Product Info Catalog Hardware Builders Hardware Springs Extension Springs, 7/16-In. OD x 3-1/2-In., 2-Pack Extension Springs, 7/16-In. OD x 3-1/2-In., 2-Pack Request a Quote UPC: 38594001394 SKU: 681163 Model Number: C-139 2 Pack, 7/16" OD, Extension Spring, 3-1/2" Length, .054" Wire Diameter, 2.41 Maximum Deflection, 12.01 LB Maximum Safe Load, Polybag.