This is what the complete picnic tap package comes with as standard.
Your release gas from a 16g CO2 cartridge by pushing the button, you are the regulator.
After a couple of goes they are actually quite easy to use and are also useful for flushing a mini keg or growler with CO2 prior to filling with beer.
Use them in very short bursts, it is easy to over pressurise a keg using this if you press too long.
The outlet is M8 thread and needs an adapter if you want to use it on an MFL disconnect