GSM Laser Boresight 20 Gauge 
  
For use on .17 to .50 caliber and 10 12 & 20 gauge shotguns
  
Includes Calibration Target and Carrying tube
  
Green lasers project brighter and are highly visible at  long distances
 
End Of Barrel Laser Bore Sighting Systems
  
Patented design
  
Durable machined aluminum construction
  
Unit includes (3) three LR44 Alkaline button cell batteries
  
No metal on metal contact will not scratch the finish of the barrel or damage your rifling