I use a 100% offset just about every time I do a contact session with no issue. Amplitude as high as you can go to boot. OUT1 +100% offset at 10V and OUT2 -100% offset at 10V with INVERSE+SYNC combining the two outputs via Boost.
Some people out there were getting skin burns after using 100% offset programs for extended periods of time. I've known people who have gotten burns and once got them myself when I used old pads. In that particular case it was zapping (7 minutes on, 20 minutes off, 7 minutes on, 20 minutes off, 7 minutes on). Now my zapping routine is 10 minutes on, 20 minutes off, 10 minutes on, 20 minutes off, 10 minutes on and for whatever reason, I never get burns.
I'm not sure exactly what causes them but staying hydrated and using new TENS pads seems to do the trick. When the pads barely stick anymore, it's time to move on.
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