The advantage with these sq tanks is that you can get more fuel into a smaller space than is possible with the bottle type tank.
The filler & breather are moulded into the forward recess, which stop either being kinked.
A tidy tank can be used with a T Joiner to pressurise the tank from the silencer.
The lower line is the feed & the upper goes to the silencer pressure nipple.
Two extra outlets are moulded in which if drilled out could be used to join two or more tanks together.