I bought one of these with the metal stand. When it arrived it did not work. After some negotiation I got a partial refund sufficient for me to buy just the head unit.
I took the head unit apart this morning. The lithium battery was never fitted to the unit. There is a contact adhesive foam mount for the battery with the film still in place and there are no battery leads installed on the board.
I won't know about the sensor until I get a working unit, but the LCD display works. Except for the LED which is a small 2 wire header, all the connections are fine pitch flexible cabling, so replacing the main board would be very simple.
Despite it being known at the factory that it did not work, it was packaged with all the accessories and sold to a merchant doing business on eBay. Naturally there is no mention of the manufacturer anywhere on the package or instruction slip.
Edit: The back of the unit has a label Shenzen Gao Suo digital Co., Ltd