This is a hotshoe mount for a laser pointer. My use case is to mount a green laser to a camera to help point the camera for astrophotography, but you might find some other photography uses for it.
My laser pointer has a button that sticks out. The mount has an extra lip that you can rotate into position over the button, and keep the button pressed down (but be careful not to blind anyone with the laser, or to leave it on where an airplane might pass).
The mount is fully customizable so if your laser has different dimensions, or your hotshoe/printer has different tolerances, you can adjust it.
I used this to help with some simple photos I took at a darkish location. At 140mm zoom on a micro-4/3 camera, the precision of the mount and/or hotshoe was not enough to put the beam in the field of view. At more moderate zooms, the beam showed up nicely in the field of view--see the picture of the beam pointing to the Orion nebula.
The pictures were one minute exposures using an unmotorized barndoor mount. The green line is the laser. Note the faint meteor (I assume) track in the second--I didn't see it naked eye, but I was looking at the mount, nor the sky.
I had some focusing problems which you can see if you zoom in. On reflection, maybe the tip of the laser beam is far enough away to help with that, by letting one focus on it. I didn't think of that at the time--I just set the focus theoretically to the infinity range.
The duct tape on the tip of the laser helps hold in place an IR block filter I glued on the pointer, as my pointer was one of the cheap ebay ones that don't have an IR block filter (which makes them way more dangerous, as they emit more in IR than in green, and hence can damage eyes even more).