Abstract: Adapter allowing a physically smaller standard size battery to fit in an application where a larger physical sized battery would normally be needed. The adapter is a simple two-piece construction which can be economically manufactured from plastic and has a full-sized solid electrical contact which prevents it from being impaled on coil spring terminals used in some battery compartments. The smaller adapter allows a standard AA size battery, or a standard AA size rechargable cell, to be used in a C cell application and has the full-sized contact molded in place to prevent removal. The larger adapter allows a standard C size battery, or a standard C size rechargable cell, to be used in a D cell application and has a full-sized contact installed. The smaller adapter may be slipped into the larger adapter thus allowing a standard AA battery, or a standard AA rechargable cell, to be used in a D cell application.