Hello Colleen, thank you for reaching out to us and I'm glad we were able to resolve your issues with pad use. To reiterate, please always make sure the Mega Pads are used as a pair - they will not work correctly and sensations will be extremely dull, if they can be felt at all, when using both clips from the same electrode wire on one pad.
“Hey guys I’ve used these larger pads a few times and there great.
But I think that because my Hi-Dow unit is quite old it wouldn’t power 4 of the larger pads.”
Thanks for your review Terry! The Mega Pads must be used as a pair to feel them working at full strength. If your unit does not have dual A/B ports then you only need to use 1 set of electrode wires with the pads as using 2 wires will cause it to short out. Hope this info helps!