Product Info Catalog Hardware Builders Hardware Springs Extension Spring, 7/8-In. OD x 9-In. Extension Spring, 7/8-In. OD x 9-In. Request a Quote UPC: 38594003336 SKU: 639807 Model Number: C-333 7/8" OD x 9", Extension Spring, .135 Wire Diameter, 2.69" Maximum Deflection,78.9LB Maximum Safe Working Load, Bulk With UPC.