Product Info Catalog Hardware Builders Hardware Springs Extension Springs, 3/8-In. OD x 4-In., 2-Pack Extension Springs, 3/8-In. OD x 4-In., 2-Pack Request a Quote UPC: 38594001936 SKU: 681353 Model Number: C-193 2 Pack, 3/8" OD, Extension Spring, 4" Length, .034" Wire Diameter, 6.66" Maximum Deflection, 4.13 LB Maximum Safe Load, Polybag.