What is this shifter

Pardon my ignorance, but what kind of shifting mechanism is this and how does it work. Thanks

 

air shifter
Press a button to fire the cylinder.
Ratcheting, inline shifter, start in 1, bang 2, bang 3, etc.
You can even fire it on an rpm activated switch.
On motorcycles we used the same relay to cut ignition for a moment to unload the drivetrain so it can shift without the clutch. A little hard on parts, but if your'e serious about shaving every tenth, it works.