As others have said, if you want a 2 litre, then buy the 3 litre, as all sizes given are external. I filled mine to what I assume is the mark, and it took 2 litres, but other reviewers have said they are fine filling the tank with 2.5 litres of water. I think I’ll stick with 2 litres.Having said that, it seems a fairly useable space, and I gave it a test run on an old oil filter removal chain. I only gave it 3 minutes at 34C, but even in that short time it shifted some vintage muck.It doesn’t seem too noisy at all, especially compared with my little plastic ultrasonic cleaner. It also makes a slightly scary fizzy noise, but apparently it’s meant to.Helpful hint, fill with hot water, and let the heater keep it warm. As someone else has said, it’s not a kettle, so don’t expect it to heat from cold within your lifetime. I got this one through Amazon Warehouse, and all seems fine, and at a bit of a reduced price.Why didn’t I give it 5 stars? The beepy alarm for the timer is ridiculously loud, with no adjustment. Otherwise it seems not too bad at all. It doesn’t have all the bells and whistles that some have, but I’m happy with it.