Product review (3 stars): Updated Fahrenheit conversion instructions!
Works great after conversion. Mine (bought in August 2016) has a different board than the other guy with instructions to change over to Fahrenheit. On this board, there's a tiny spot marked with an "F" (see attached picture) that I jumped using a very small piece of tinfoil. The foil was folded over to make it smaller and taller, then held on with some electrical tape. It wouldn't work with just one battery but if you put the display and circuit board together then hold the batteries in place with two fingertips, you can get the display to come on and see if it worked without messing with the back case.