Medco M4 cylinders are UL Standard 437 listed for physical strength and high security, with solid brass machined construction and strategically placed hardened-steel inserts to thwart drilling attacks. In addition to tumbler pins that lift and rotate, the M4 design includes four side pins: three finger pins and one lift pin, which must all interact with the sidebar to open, providing a high level of pick resistance.
Horton Automatics: BH Slider
Kimball International: Shore
Protimeter: Aquant
Sensaphone: Sentinel PRO
KI: Passel