A common addition to a defensive longarm is a weaponlight to assist in identifying threats in low light conditions. One simple way to accomplish this task is with the Magpul Rail Light Mount.
Constructed of polymer and aluminum and compatible with Magpul's XTM panels, the Rail Light Mount is available for either right- or left-handed shooters. The mount places the light at the 11:00 position (or 1:00 position, depending on which hand is used) and can be placed where most convenient for the support hand to reach. There's even a textured section for resting the support-hand thumb for fast access to a tail cap switch.
The Rail Light Mount will accept SureFire's Scout Light weaponlights, flashlights with integral Picatinny mounts and any flashlight with a tube diameter between .75 and 1.04 inches. Whichever light is attached will be kept high and close to the bore to minimize shadow, and can be positioned wherever needed. MSRP: $29.95.