Product Info Catalog Hardware Builders Hardware Springs Extension Springs, 3-In. OD x 5/16-In., 2-Pack Extension Springs, 3-In. OD x 5/16-In., 2-Pack Request a Quote UPC: 38594001554 SKU: 843870 Model Number: C-155 2 Pack, 5/16" x 3", OD Extension Spring, 028 Wire Diameter, 5.37" Maximum Deflection, 2.85 LB Safe Working Load, Poly Bagged.