Electric comb?

Hi Ladies.  I was wondering if anyone out there has ever come across an apparatus that is like a comb or a piece with a comb attachment that emits electrical pulses.....When I was in college about 12 years ago, I came across a hairdresser that I always say came from the heavens because she worked such a miracle with my hair...she used such an apparatus.  I ate gonna lie, it was a bit uncomfortable having electrical pulses administered to my scalp.....but I kid you not....It made my hair grow like wildfire.  I never experienced hairgrowth as fast as that ever.  And I am talking about after coming out of a bad perm with broke off my hair very badly.  She restored my hair to a point where it was long and thick and healthy.  Unfortunately, I lost touch with this hairdresser over the years, but I would give anything to find out what that thing was she used on my head.  My hair has seen some tough times lately with me transitioning from a relaxer to natural, as I am sure some of you ladies can atest to.  Can anyone help me out with this?