Keep your wireless Comfort Contego FM HD Communication System powered with this add-on accessory. Comfort Contego is a digital, secure communication system for hearing aid users with a t-coil or users with hearing loss using a headset. It uses coded radio transmission that makes it virtually impossible to intercept a conversation. The wireless feature makes it a practical solution for work, school, restaurants and other noisy environments, and for TV/sound systems. Ninety day warranty.