The Shark Laser with a laser clamp
Mounting the Shark Laser on a spear gun or as doubles on a rig to measure fish is just a matter of using your imagination

This clamp rotates 360 degrees to point the laser in any direction from the bar/

The Shark laser snaps into the grip while the clamp jaws have a threaded bolt to adjust it to a bar.

Mounted parallel to bar, possible mounting for a spear gun depending on your ingenuity.

Mounted at 90 degrees from bar for rigs such as the one seen below.

Two clamps used to mount lasers side by side to project beams for measuring live fish or other underwater objects.