New design that complies with all new and upcoming california laws by forcing the action to be opened for use!!This California Compliant Magazine Lock for our C-9 lower receivers converts the detachable magazine system to require the user to slightly pivot the upper receiver open to release the magazine. The magazine lock can be used on the New Frontier Armory C-9 Lower Receivers after removing the stock magazine catch.This lock will work with ALL uppers.This lock is manufactured from billet aluminum and features a black hard anodized finish. You can reuse the stock magazine catch spring and magazine catch threaded pin. Simple install - Use your existing mag catch spring and threaded pin to install this catch. The Battle Arms Quick Release Rear Take Down Pin is a perfect add-on complement.The California Compliant Mag Lock MK1 (C-9) is proudly MADE IN THE USA by hard working American men and women.Specifications: Model: California Compliant Mag Lock MK1 (C-9) Weight: .05 lbs Dimensions: 3 x .25 x 6 in