Perst-4 is used to point targets when observing , inspecting and watching small arms shooting at night. This product is a small optical mechanical device that forms laser radiation flux. This product is installed on Picatinny rails. The KV-D2 Tactical swtich (in the kit)can be installed on picatinny rails and 1913 rails. Perst-4 contains 2 laser functions: Green Laser light source: wavelength - 635 nm IR light source: wavelength - 850 nm Power supply: CR123A (installed) / battery (3 V). Effective range in the dark: red beam: 300 ± 100 m.; IR beam: 400 ± 100 m. Product weight without batteries: no more than 210 g. Overall dimensions: (37х60х91) ± 3 mm. 1. The triangular area on the host can switch between visible laser and IR 2. On the top or side of the host , the round switch is turned on. Turn on through the KV-1P Wire Control Switch 3. Press the swtich quickly to realize the strobe function 4. Two small circular buttons on the main unit to adjuest the laser brightness . Custom Bundle: No Fit For: 20mm Picatinny Rail Material: Metal