This is a clamp to mount a laser pointer to a Cold Steel blowgun or any other blowgun with a 19 mm diameter tube for easier sighting.Made to work with a cheap pet-store laser pointer. Use 6-32 nuts and screws. You can turn the laser on temporarily by pushing the button, or keep the pointer on by pushing the pointer from the back into to mount. There is a small ramp inside that will hold the button down. Pull the pointer back to turn it off. Warning-I found out the hard way that the lasers in cheap laser pointers are not inline with the axis of the pointer body. So, while the body of the laser pointer may be perfectly inline with the bore of your blowgun, the laser dot may point somewhere else. You may need to shop around to find a laser with proper alignment.