I decided that if one is good, two may be better.
Wrong.
Unless you have a way to activate them at exactly the same instant, I can vouch that they will operate out of sync.
I got an upset tummy and a temp of 99.8 in my right ear, and 99.6 in my left.
It was almost like being seasick, but I'm not sure, 'cause I've never had that malady.
Now, just how close can two safely/effectively operate near each other?
What if you live in an apartment and your neighbor gets one, too?
What a mess.
