In 2009, Botswana-based company Deaftronics launched a solar-powered hearing aid after six years of prototype development. Since then, Deaftronics has sold over 10,000 of the hearing aids. Priced at $200 per unit, each hearing aid includes four rechargeable batteries (lasting up to three years) and a solar charger for them. The product is inexpensive compared to many similar devices, that can start from around $600.