The ETM Heavy Duty/+P .45 ACP magazines feature Wilson Combat's exclusive stainless flatwire MAX magazine spring paired with a time-tested stainless steel ETM tube. Engineered for extreme reliability, these 8-round magazines are designed to never require replacement, even under high round counts, daily use, or +P loads. The heat-treated MAX flatwire construction provides up to 25% more strength than standard 1911 springs, ensuring superior feeding, positive slide lockback, and consistent performance over the magazine's lifetime. Extensive testing by the Wilson Combat Shooting Team confirms unmatched reliability, while the stainless MAX spring offers exceptional corrosion resistance, even in high-humidity or marine environments. Black models are finished in durable black nitride QPQ, a wear-resistant, non-reflective coating that will not chip, crack, or peel, providing a tough, long-lasting surface. These magazines set a new standard for durability and performance in .45 ACP 1911s.