Much like the full size m&p series lasergrips for s&w pistols, these are interchangeable between different calibers of sub-compact m&p pistols and directly mimic the look and feel of the original grip, with the tactical impact of laser sighting.The rear-activation switch is part of a natural grip, so there's no fumbling to activate the laser with your trigger finger.The lg-661 fits s&w m&p compact 9mm, 40 s&w, 357 sig models, except for 45 compact and ambidextrous safety models.Does not fit m&p m2.0 models.Wavelength: 633nMDot Size: .50" @ 50 ydsPower: 5mWRange: 50 ftWeight: 1 ozBattery: CR2032 Lithium (2)Laser Color: RedFirearm Fit: S&W M&P CompactAdjustments: Windage & ElevationFinish: Black Rubber OvermoldMount Type: Grip