I bought mine here.

hxxp://www.e-stim.co.uk/index.php

exchange x's for tt's

They're fairly cheap and I'm very happy. I'd tried them out many times at various expo's before going for it.

My slave never liked them, so it never caught on. It was a fun experiment. But we did find another great usage for it. Electro stimulation of the back muscles is great for relaxing. Switching between on and off is a great way to relax tired and tight muscles.

It's doesn't hate to hurt. Low stimulation only feels great. A tingling sensation. The "width" of the pulse regulates the sharpness of it. I always set it to the widest setting which feels best.

It's kind of scary to send signals over the heart. You can feel something ain't right. A prickly, nasty sensation. Scary as hell. I just did it as an experiment.