Abstract: A stand-alone portable radio telephone unit, includes an upper part, and a lower part. The upper and lower parts have similar peripheral shapes and in combination include all of the components necessary to form a handset for connection with a main unit in a mobile phone system. An intermediate part is located between the upper and lower parts and includes radio frequency components, an antenna and battery means. The upper, lower and intermediate parts in combination include all of the components necessary to form a stand-alone portable radio telephone unit. Bringing the three parts into abutting engagement completes the required electrical connections between the parts.