2pcs High Voltage Generator DC 3V-6V-400kV 400000V Boost Step-up Power Module High Voltage Transformer

i made something amazing with these and theyre fantastic

Running off a 3.7V Lion and tested the output voltage with a meter specifically designed for high voltages (electric cattle fences). Doesn't come anywhere near 400,000. It could barely reach 4000. So yeah, not quite as advertised.

These work perfectly. At 5V they draw about 1-2A and will arc about 1-1.25”. That suggests that they are more like 200,000V, but still loud and very cool. Trivially easy to use and wire up. Cannot speak to durability, but so far, they haven’t fried.

it can shock you alright

I mean, yeah. It's a taser. Probably hurts like a mother. I recommend a single 3.7v lithium battery like either of the two in the image. These can deal with the significant current draw the device likes, and should not overvolt it in my experience. Keep the output leads less than a half inch away when getting things set. If there are too far away, you're gonna destroy the device. So start with a small gap and work your way up. With a 1.5 inch gap this thing snaps about as loud as a .22, likely louder than some. A nice intimidating crack like ripping a sheet of paper. Easily 1-2 a second with a good battery. Good qualities for self defense should one want to go that way.