Product Info Catalog Hardware Builders Hardware Springs Extension Spring, 7/16-In. OD x 8-1/2-In. Extension Spring, 7/16-In. OD x 8-1/2-In. Request a Quote UPC: 38594003152 SKU: 681718 Model Number: C-315 7/16" OD, Extension Spring, 8-1/2" Length, .047" Wire Diameter, 9.3" Maximum Deflection, 8.47 LB Maximum Safe Load, Bulk With UPC.