I should add that if you go look on FT, there are two different models. One has an inhouse 50W chip that is similar to a
dna chip and uses up and down power buttons. The other uses the Yihi sx300 chip, which works via a G Sensor.
I don't know how good or bad the SXK chip is. Their first chip, which was 30W wasn't great. It read resistance wrong, had a delay to fire and no memory so everytime you change the battery, you had to remember to reset it.
The Yihi chip has memory, and is accurate. However, it does read high on the battery indicator.