Product Info Catalog Hardware Builders Hardware Springs Extension Springs, 5/16-In. OD x 5-In., 2-Pack Extension Springs, 5/16-In. OD x 5-In., 2-Pack Request a Quote UPC: 38594002896 SKU: 639799 Model Number: C-289 2 Pack, 5/16" OD x 5" Extension Spring, .034 Wire Diameter, 5.44" Maximum Deflection, 4.91 LB Safe Working Load, Polybag.