Looking at the Mantis X shooting trainer.
The mantis-X has multiple versions designed for dry and/or live fire training. To do dry fire you can use the X2. To also do Live fire you need the X3 or the X10.
What is the concept? Basically the sensor detects what your gun (you) are doing right as you break the trigger. It then saves/compares this data to help evaluate your shooting.
Ex: "Too little trigger finger."
I am a certified NRA basic pistol instructor (though I rarely do anything with that) and help instruct the Intro to Competition Class when my local range, Volusia County Gun Club, hosts a class each month. A significant number of the people taking the Intro to Competition class should probably be taking an intro to shooting class instead. Helping them sort out why they are shooting a foot low-left of the plate every time is half the battle. The Mantis-X would seriously help!
The Mantis is designed to attach to a rail. If your pistol doesn't have a rail, they have magazine baseplate adapters.
Disclosure, I do not have a Mantis yet. But, it's definitely on my to-do list, as a personal shooter to catch issues, and especially when helping newer friends/family shooters. Or, for my occasional individual instructing I think it would extremely helpful. I plan on having one soon and will update this to a "review" at that time.
Below is one of their youtube videos (they have a lot available).
And a link to their product comparison page :