Product Info Catalog Hardware Builders Hardware Springs Extension Spring, 5/8-In. OD x 8-1/2-In. Extension Spring, 5/8-In. OD x 8-1/2-In. Request a Quote UPC: 38594003237 SKU: 681759 Model Number: C-323 5/8" OD, Extension Spring, 8-1/2" Length, .080" Wire Diameter, 5.2" Maximum Deflection, 25.6 LB Maximum Safe Load, Bulk With UPC.