yes the cylinders on the BOC hobbydeal are 20L.
they do a 10L also.. X size..
a Y size cylinder took me 12 - 18 months to use.
now with a TIG set too..... these cylinders take up space.
its why i thought il try two 10L cylinders first.
if needed i can swap the two 10L ones for a 20L cylinder.
then take out another 20L cylinder for the other gas.
but il see how long they last me first as they dont take up as much space.