The Crimson Trace(R) LG-420G Laserguard(R) is a powerful green laser sight for the Sig Sauer(R) P320 pistol” (also known as the M17 in full-size and M18 in compact). The LG-420G is quickly and easily user-installed in moments and offers a front activation button powered by Crimson Trace’s Instinctive Activation(TM) technology. The laser sight will provide two (2) 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-420G is completely user-adjustable for windage and elevation. This model features a Master On/Off switch for completely powering down the unit to train without the laser sight. Fits all P320 models except subcompact frames.