Masks Noise - cancel out noises that might disturb or distract, for improved sleep and concentration. 3 Sound Options - Bright white noise, deep white noise and gentle surf. Portable - Perfect for travel and on-the-go use (includes lanyard for easy handling or hanging). Rechargeable - Convenient USB charging (USB cable included). Guarantee - Backed by a one-year limited factory warranty and the always exceptional Marpac customer service promise.