Product Info Catalog Hardware Builders Hardware Springs Extension Spring, 7/8-In. OD x 8-1/2-In. Extension Spring, 7/8-In. OD x 8-1/2-In. Request a Quote UPC: 38594003299 SKU: 681775 Model Number: C-329 7/8" OD, Extension Spring, 8-1/2" Length, .105" Wire Diameter, 5.56" Maximum Deflection, 40.1 LB Maximum Safe Load, Bulk With UPC.