Choose What’s Best For You. The XM is a waterproof switch assembly for SureFire's Millennium Universal and Classic Universal WeaponLights. It includes a system disable feature, click-on/off pushbutton switch and a plug-in momentary-on remote tape switch. The pushbutton and pressure-activated tape switches operate independently, providing switch redundancy. When choosing an XM switch model, the two digits after the "XM" indicate the cable length in inches. For example, the XM07 has a 7-inch cable. The seven-inch cable length works with most rifle/carbine applications. Fits Millennium Universal and Classic Universal WeaponLightsPush-button and pressure-activated tape switch operate independently, providing redundancyMultiple cable length options to fit a wide variety of rifles and carbines SureFire XM07 Remote Dual-Switch Tailcap Assembly w/ Momentary/Constant On/Disable Modes & ST07 Tape Switch for WeaponLights XM07