The Evi-Paq½ trajectory kit is the only kit in the market that provides co-aligned penetration rods, meaning your centerline will always be straight without deviation. The aluminum rods are center drilled to give a straight line each time. The Evi-Paq½ BP-1 laser trajectory pointer is a unique high-power laser pointing device with an ultra-bright beam that is specifically designed to assist an investigator in the determination of the source and trajectory of bullets at a crime scene. Its design allows it to be used in conjunction with the tripod mount, protrusion rods and trajectory kit. An innovative design feature places the on-off switch internal to the unit, which is activated when a steel connector is screwed into place at its base. There is no external switch that may be prone to breakage or failure. The BP-1 unit is powered by a pair of inexpensive N-size 1.5 volt alkaline batteries (included) which provide approximately 11 hours of continuous power-on use. Unlike other lasers, the BP-1 laser's special diode is co-aligned with its aluminum case and is four times more powerful, making it easy to photograph. Using the Evi-Paq½ tripod mount, BP-1 lasers can be placed in open space and aimed at and through a bullet hole. BP-1 lasers can be attached to any of the four sides of the tripod mount to help determine both the source and destination of the bullet. The tripod mount eliminates the need to have someone hold the laser. Use our Photographic Fog during photography to make the entire laser beam visible. Contents: Four large diameter connecting rods, suitable for use on holes produced by weapons down to .32 caliber. Can be connected in succession or used alone. Four sets of spacer cones and O-rings: spacer cones are used to center the rods within each bullet hole. O-rings will keep the rods in place without slipping. Tripod mount with centered connecting holes to keep the rods and laser co-aligned. Can be used with either the rods or the Evi-Paq½ BP-1 Trajectory Laser for setting known angles. Angle finder used to measure the results for documentation. Will either fit on the rod or can be attached to the tripod mount with adhesive wax. Evi-Paq½ trajectory laser, guaranteed to be center aligned from the factory.