Check the listing for details. Crossbow Archery Red Laser Bore Sight Tool Threads onto Bow Arrows BoreSighter. Condition: New. Listed at 14.95 USD. Descriptions:Construction : brassLaser wavelength (nm) : 632-650LED type visible red laserPower (mW) : Battery : 3x LR41(AG13)Operation : on/off end cap Length: 4.25"Weight: 0.9 oz. Arrow laser sighting tool for compund bows, cross-bows and all thread bows. Laser unit fits directly on to the arrow Easy to use. Simply place batteries in end cap twist end cap to turn on and place in chamber The Laser Gives You The Ability To Fine-Tune Arrow Sights without Shooting an Arrow. No More Losing or Damaging Arrows. Hit the Target with your First Shot! Arrow Laser Mounts Directly to your Arrow by using the Threads in the Insert. A Very Straight Arrow and Spin Tester must be used to Achieve Perfect Alignment of the Laser Beam and the Arrow Shaft Before it can be used. Arrow Laser Aiming Device with Batteries Included.