Laser output less than Laser wavelength (nm) : 645nm, 632nm (.223 20X)LED type  visible red laserPower (mW) : Battery : 3x LR41(AG13)   1 extraOperation : on/off end capMinimum Range for Sighting: 15 ydsMaximum Range for Sighting: 100 ydsBattery Life: ~ 20 minLaser Type:Visible Red LaserConstruction: Brass   IT PROJECTS A STRAIGHT LASER BEAM ALLOWING PRECISE OPTICAL ADJUSTMENTSGREAT FOR THE RANGE AND ENSURING YOUR WEAPON IS STILL ZEROED IN AFTER TRAVELSIMPLY PLACE BATTERIES IN END CAP-TWIST END CAP TO TURN ON-AND PLACE IN CHAMBER   How to zero your bow and crossbow.Bow1). Use a new and/or a straight arrow. screw on the arrow laser  sighting tool.2). Turn on the laser beam.3). Aim the laser beam at a target and adjust the sight pins to  lineup with the laser dot on the bullseye.”Recommended distance  is 35 yards indoorNOT FIRE YOUR ARROW.4). take your bow out to the range and test fire, fine tune if  needed. Crossbow1). Use a new and/or a straight arrow. screw on the arrow laser  sighting tool.2). Turn on the laser beam.3). Aim the laser beam at a target. Line up your sight or scope  up to laser dot on the bullseye.”Recommended distance is 35  yards indoor.” DO NOT FIRE YOUR ARROW.4). take your crossbow out to the range and test fire, fine tune  if needed. Package includes: 1 x laser4 x Batteries EROCK Archery Crossbow Bow Arrow Red Laser Sighting Tool Boresighter Bore Sight