Wilson Combat ETM Heavy Duty / +P rated .45 ACP magazines with exclusive stainless flatwire MAX magazine spring and our time-tested stainless steel ETM tube are guaranteed to never need replacement. Testing has shown these to be the most reliable 8 round, .45 ACP 1911 magazines in the world.
The heat-treated MAX flatwire construction never gets stressed or over-compressed like a conventional spring and is guaranteed to never require replacement even after high round counts or daily, extreme duty use.
Maximum strength-up to 25% stronger than standard 1911 mag springs for superior reliability with defensive and +P loads and more positive slide lockback.
Maximum longevity MAX flatwire spring will never lose optimum feeding tension as long as you own the magazine -guaranteed! Extensively tested by the Wilson Combat Shooting Team and testfire crew.
Maximum corrosion resistance-heat treated stainless MAX spring won’t corrode in high humidity or marine environments-a leading cause of service pistol spring fatigue.
Read more at http://shopwilsoncombat.com/45-ACP/products/378/.