Are you getting a TENs mainly for pain blocking?
What about a combo TENS/IF unit?
[IF Combo combines Tens and Interferential to give you the best chance of treating patients that may need something stronger than a Tens unit.]
If you can afford it there's a IF/TENS combo unit that looks really nice.
http://www.amazon.com/InTENSity-IF-C...=pd_sbs_hpc_11
I have an EMS and I wish I would have gotten an IF unit instead, but I didn't have a Amazon or Ebay account back then...
Info page on types of Electrical stim units -
http://vitalityweb.com/backstore/Muscle-Stimulator.htm