Shield Arms is an American manufacturer based in Bigfork, Montana, producing firearm accessories and rifles. The company is best known for the S15 magazine, a steel Glock 43X/48 magazine that holds 15 rounds without extending beyond the grip. Other products include magazine release upgrades, slide stop levers, and Glock-compatible parts machined from steel. Shield Arms also makes the SA-15 rifle, an AR-15 platform with a free-floating handguard, ambidextrous controls, and a focus on accuracy.