Covers approx. a ten foot diameter circle around you. Self-sufficient (no battery). Smaller than a cellphone and is designed to protect you from radio waves emitted from cellphones. You can carry it in your left pocket, in your purse, or on your night stand while you sleep. Helps balance your aura. Designed to protect you wherever you go. Approximately  2 1/4 inches long, 3/4 inch diameter, with a convenient clip to hold onto your clothing.