Never used. LightStim for Wrinkles provides rejuvenating wavelengths of light energy to treat fine lines and wrinkles. Over time by using your Light you can help to recapture a plump, youthful appearance. LED is non-invasive, painless and requires no recovery time. This Light is good for all skin types and is engineered to emit a soothing, gentle warmth. LightStim for Wrinkles utilizes wavelengths of Amber, Light Red, Dark Red and Infrared with a total of 72 LEDs. No batteries to replace, simply plug in and there is an on/off switch also comes with collagen peptide serum to use with it if you choose. LightStim website states states LED are designed to last a lifetime.