Standard 20# Propane tank (like you get at a Gas Station Tank Exchange).
The following dimensions on the model match the tank I have to 1/16":
Overall Height & Width; Bottom Ring Height & Width;
Protective Collar Height & Width; Valve Height & Valve Knob;
Bottom Ring on the model is exactly like the one on my tank.
The protective collar on the model is ALMOST exactly like the one on my 20# tank.
The only difference being that my model collar has 2 handles and 1 'hole',
while the tank collar has one handle and 2 'holes'. I cut&pasted that collar from
my 40# tank, made a couple small mods to match my 20# tank, and just figured
some 20# tank collars probably have 2 handles and 1 hole anyway.