Yes, it is very similar to a TENS unit they use to short circuit nerves and stop pain, or the belts and things people wear to rehabilitate muscles with electric shock. The difference is that those devices tend to induce numbness, where an ESTIM unit is meant to deliver pleasure (or pain if you wish) without causing numbness (or any harm). BTW the units you see online are overpriced and do not work well. Building a stereostim unit is cheaper (about $20) and much much more effective. An estim orgasm is the closest I have ever come to having a supernatural experience. Sex is obviously better because it involves passion and intimacy, but in terms of pure pleasure, estim is light-years beyond.