Eemann Tech Single Stack Magazine Spring for 1911, .45AUTO The Eemann Tech Single Stack Magazine Spring available at Range Junkie is designed for 1911 pistols and their clones, offering enhanced performance and durability. Specifications: Caliber: .45AUTO 14 coils Made of steel, with thermic treatment for optimal performance and quality Varied, progressive structure provides constant pressure with greatly increased spring performance and life Magazine spring made of steel according to UNE10270-1-SM norm, with thermic treatment +25% stronger than the factory magazine spring Extra power magazine springs help improve feeding with extra power recoil springs and when factory springs have weakened No fitting required and instant installation in most cases. In some cases, pistols may differ in production or be pre-modified and may require the assistance of a certified gunsmith for installation.