The TENS machine is Much safer, a good box (which can be a couple hundred dollars minimum) has a bunch of different wavelengths, amp, and voltage. + if you ever get injured that's what they're designed for. But the Violet wands can cause physical harm really easily, although they are a much better alt. (because they're fairly cheap I believe) then fashioning yourself some kind of electro therapy out of Radio shack items. Which people do, do and i don't know why.