The Scattergun Technologies Magazine Tube Spring for the Remington 870/1100/1187 is an extra power spring for reliable operation with a magazine extension. 1 shot extension for use with +1 extended magazine tube, 2 shot extension used with +2 extended magazine tube. This product is designed to provide reliable operation while also delivering maximum results. This extra power spring is designed to replace the factory spring for improved feeding of all types of shot shells, from target to magnum loads. This spring also helps reduce the risk of jamming in adverse conditions. Made with advanced heat-treated, 17-7 stainless steel, this spring is built to last.