Kit (Tank))
From Unofficial Stationeers Wiki
Tanks are used to store large amounts of gas.
Given that pipes will burst if the pressure differential between the inside pressure and outside atmosphere is greater than 60,795KPa (plus a random check to allow for short bursts over this limit), this is also a limit for the tanks, as you will lose all your gas if the pipe connected to the tank ruptures.
There is a large tank option that uses 5 kits.