I picked up an ElectraStim Aura mistakenly thinking it was self-powered, but rather than return it I'd rather see why it came so recommended. My only previous experience with estim is with the Leyuto Beating Mango which is too much for me even at the lowest intensity, so I don't need much power and thus was looking at TENS units.

Trying to decide between the TENS 7000 (https://www.amazon.com/gp/aw/d/B00NCRE4GO) and the Intensity At Home (https://www.amazon.com/gp/aw/d/B079YYJQWM). They each seem to have their strengths but knowing whether I need symmetrical or asymmetrical or square or rectangular waves or pulses is beyond my understanding. How much does pulse width, amplitude, and rate matter or even mean? I've read up on this as much as possible but still have no real idea which would be better for me or if there's even enough difference between the two to notice.