The ETM Heavy Duty/+P .45 ACP magazines from Wilson Combat are engineered for unmatched reliability and durability in 1911 pistols. Each magazine features Wilson Combat's exclusive stainless flatwire MAX magazine spring paired with a heat-treated stainless steel ETM tube, designed to deliver maximum performance under extreme conditions. These 8-round magazines are built to withstand high round counts, daily use, and +P loads without stress or over-compression, ensuring consistent feeding and positive slide lockback. The MAX flatwire spring provides up to 25% more strength than standard 1911 springs, maintains optimum tension throughout its lifetime, and offers superior corrosion resistance even in high-humidity or marine environments. Extensively tested by the Wilson Combat Shooting Team, these magazines are designed to redefine reliability for any .45 ACP 1911 owner