I've been reading about the use of T.E.N.S (Transcutaneous electrical nerve stimulation) units for the use of musculoskeletal and arthritis pain and am wondering if anyone here has tried it for alternate pain relief?

Its a little wearable unit that takes a 9 volt battery and has 4 leeds (wires) and 4 electrodes (pads with sticky jelly on them), it transmits electrical pulse through the skin.
Its supposed to stimulate nerve fiber and temporarily block the transmission of pain to the brain... Its a very minor treatment and also very localized but could it help?

The reason I ask is that I started working in a physio clinic doing billing and admin work and I noticed them in the inventory.
I was thinking about sending one to my mom to try but I'm wondering if this would help, hinder or just be ineffective?

Does anyone have experience with this or any thoughts on it?