Product Info Catalog Hardware Builders Hardware Springs Extension Spring, 9/16-In. OD x 16-1/2-In. Extension Spring, 9/16-In. OD x 16-1/2-In. Request a Quote UPC: 38594002537 SKU: 681494 Model Number: C-253 9/16" OD, Extension Spring, 16-1/2" Length, .054" Wire Diameter, 25.2" Maximum Deflection, 9.5 LB Maximum Safe Load, Bulk With UPC.