Hot shoe dual axis bubbly thing tipA tip for the people who don't have one yet; I just found this
spirit level for $25 on Ebay.
I paid $25.00 on ebay for mine 2 years ago I could not find one in a shop in Australia. Actually from memory the bloke on ebay didn't charge me freight. I'm sure someone in China would make them and would be cheap you just have to find them.
I have also seen them with circular bubble level in place.