This is a air driven solder paste dispenser with suck back for precise solder droplets. Size of droplets and repeat interval are set on the front panel. Dip switches on the back control 16 different modes.
Seems to be exactly the same at similar 983a dispensers on aliexpress but a whole lot cheaper in Shenzhen. Manual is Chinese only but the good parts are translated over at eevblog forum.
Solder dispenses when the foot pedal is pressed. Pretty typical. But it also has a finger trigger that slides over the solder syringe. Didn’t notice that when I bought it.
This needs an air compressor with at least 70psi but preferably 100psi. That won’t get here until tomorrow.