The Signia Cellion primax is one of the few hearing aids on the market that is powered by a built-in lithium-ion battery. This means with the Cellion, you never have to change batteries. Simply set the hearing aid in its charger when not in use, and after a few short hours your hearing aids will provide up to 24 hours of hearing. This hearing aid requires a Cellion charger package to work. Whether you are buying a single hearing aid or a pair, a charger package must be purchased, at a price of $389. The charger package includes (1) charging device, and (1) power module for mobile charging. If a set of hearing aids is purchased, your charger package will include (2) power modules.