Had for about a year. The slight yellowing/discoloration is just the silicone yellowing because of the light. It is completely clean and works like brand new. Giving a heavy discount because of this cosmetic defect. From the manufacturer: Red light therapy mask trusted to reduce the signs of aging - reduces wrinkles, evens skin tone and smooths skin texture Gives you a healthier, brighter and smoother complexion Treats with the 2 clinically recognized wavelengths: red (633nm) and near-infrared (830nm). Flexible silicone shape