Product Info Catalog Hardware Builders Hardware Springs Extension Spring, 7/16-In. OD x 10-1/4-In. Extension Spring, 7/16-In. OD x 10-1/4-In. Request a Quote UPC: 38594003114 SKU: 681692 Model Number: C-311 7/16" OD, Extension Spring, 10-1/4" Length, .041" Wire Diameter, 17.5" Maximum Deflection, 5.6 LB Maximum Safe Load, Bulk With UPC.