When our kitten broke his leg last spring, both the vet and the orthopedic surgeon recommended he have cold laser therapy to speed his healing. The vet performed those treatments with a professional cold laser machine of some sort; our little guy did heal up very nicely, so I was intrigued. We also have several senior animals (and people) at home, and since the light therapy is supposed to be good for arthritis too, I looked for an affordable home unit. This TENDLITE LED unit was represented as being as effective as cold laser light, and the price was right, so I decided to try it on myself. Honestly, I'm surprised, but it does seem to be helping. I have been doing daily one-minute sessions on the two lower joints of my right thumb, which had been giving me trouble for awhile, and it is bothering me much less. Battery life is good on this unit (several weeks for me); it comes with a recharger too. If I'd held on to the instructions I would have realized that the lights on the recharger blink like a slot machine while the battery is charging -- I thought it was a malfunction, but my inquiry to the company was answered very quickly, and straightened out my confusion.