The Rainier Arms Magazine Advanced Release System (MARS) provides shooters of Glock Gen 1, 2 and 3 pistols chambered for 9 mm Luger, .40 S&W and .357 SIG with an aluminum release that enhances speed reloads for both left- and right-handed operation. The left-side button looks and functions like the factory Glock release while the right side utilizes a pivoting push-button. The MARS is a drop-in unit that requires minimal installation time, works with the factory Glock magazine catch spring and does not impede use with standard holsters. Price: $60. rainierarms.com.