Impressive accupuncture treatment can be found at http://hidow.com/
Buying from airport you can get ~50% discount (e.g. at Washington Dulles Airport - Terminal A&B there is a reseller: iRelax-n-Massage).
The painpod is the top of line product right now with 12 modes and 2 intensity, then the XPD with 9 modes and 2 intensity both have back lights. 2 intensity means ability to choose different intensity for different outputs. If there are 2 ports then it means 2 outputs and each output is able to feed 2 pads.
Then the XPO and Micro or neck and neck with both 8 modes 1 intensity and back lights
All of those device have 2 ports as well
The ismart 6 modes 1 port 1 intensity no back light
Painless tens is a tens device with no display screen and only 1 mode that goes through random motions.
At autumn 2015 there are coming out two new painpods - so keep tuned!
These kind of treatment is called Transcutaneous electrical nerve stimulation (TENS)
Other producers
Search
Reviews
More reading:
http://www.acupuncture.org.uk/public-content/about-acupuncture-treatment/what-to-expect-from-a-treatment.html