The Crimson Trace® LG-420 Laserguard® is a powerful red laser sight for the Sig Sauer® P320 pistol, (also known as the M17 in full-size and M18 in compact). The LG-420 is quickly and easily user-installed in moments and offers a front activation button powered by Crimson Trace's Instinctive Activation™ technology. The laser sight will provide four (4) hours of battery life with a single 1/3N Lithium battery and features a quick change battery cover for replacement without removal of the unit. As with all Crimson Trace laser sights, the LG-420 is completely user-adjustable for windage and elevation. Fits all P320 models except subcompact frames.