It was the enclosure that my bp cheddar came in. I had since upgraded him to a full 20g long, but kept it as a spare <never know when you are gonna find a reptile in need after all>. I suppose this could be a 15g. My main concern is whether or not it is too big? Have since found a better choice for a water dish though so that will be changed next.
Thanks Aaron, ever so helpful as always.