Please Help Identify BAT Pottery Mark (photo)

This small turquoise blue vase with a slightly rough texture is about 4" in size with "BAT" crudely etched in the bottom. Under that is a line followed by what looks like "2X6". I'm not sure about the 2 - it could be a Z or a J or even a 9. Can anyone tell me the maker and anything else about this vase? Thank you.