Signia calls Pure Nx hearing aids the "smallest solution for a natural sounding own voice and direct streaming". This refers to the version with size-312 batteries. The hearing aids are also available with size-13 batteries for the longest streaming time in class. These fully-featured RITE-style hearing aids feature a raft of sophisticated sound processing technologies, including Signia's unique OVP (Own Voice Processing). If you have worn hearing aids before and had to compromise between setting the volume loud enough to hear other people's voices yet soft enough to keep your own voice sounding natural, you will probably appreciate OVP. Pure Nx hearing aids are made for iPhone, meaning they can stream music and calls directly from Apple devices without the use of additional accessories.