This listing is for both the ArmaLaser GTO and the FLX17 griptouch activation switch, custom designed to fit only on the HK P30 P30L. The ArmaLaser GTO can work with or without the FLX17. If you prefer to turn the laser on/off by simply touching the sides of the laser body with your trigger finger, then you do not need to install the included FLX17. Easy 5-minute installation for GTO and another 3 minutes if also installing the FLX17. Extremely well crafted. State of the art 635nm red laser, up to 5X brighter than 650nm. The ultimate firearms laser. Experience immediate laser activation as soon as you grasp your pistol. No buttons. Battery Door: Easy battery changes. Adjustable: Both windage and elevation. Battery: 1 commonly-found CR1/3N. Pulsing and steady beams. GTO Material: DuPont Zytel FRN Polymer. FLX Material: Tough, tear-resistant DuPont Polymer with 3M non-marring, aggressive adhesive backing. Dot Visibility: 1/2" at 50 feet, Battery Life: Up to 6 hours, Output: Ultra-bright FDA Class IIIa Laser Product (Does not exceed Class IIIa emission limits), <5mW power output. Weight: 3/4 of an ounce with battery installed.