Product Info Catalog Hardware Builders Hardware Springs Extension Springs, 9/16-In. OD x 4-In., 2-Pack Extension Springs, 9/16-In. OD x 4-In., 2-Pack Request a Quote UPC: 38594001837 SKU: 681304 Model Number: C-183 2 Pack, 9/16" OD, Extension Spring, 4" Length, .047" Wire Diameter, 7.42" Maximum Deflection, 6.7 LB Maximum Safe Load, Polybag.