Transmitter-receiver earphone set having a foldable receiver unit

A transmitter-receiver earphone set e comprising:

• a narrow elongated hollow body, said body comprising a protruding transmitter unit at one end thereof, said transmitter unit having a speaker and a cable extending from said speaker toward the inside of said transmitter unit for connection to an external electronic apparatus, a narrow elongated groove extending outwards from a bottom side of said transmitter unit and terminating at a pivot end;
• a receiver unit receivable in said narrow elongated groove of said body, said receiver unit having a free end mounted with a microphone, a lock hole formed in said free end, a fixed end pivotally coupled to the pivot end of said body for enabling said receiver unit to be turned relative to said body between a received non-operative position where said free end is received inside said narrow elongated groove and an extended operative position where said free end is moved out of said narrow elongated groove, and a release control mechanism installed in said fixed end and adapted to turn said receiver unit from said received non-operative position to said extended operative position;
• a button installed in said body adjacent to said transmitter unit and adapted to lock said receiver unit in said received non-operative position, said button comprising a locking rod for engaging the lock hole of said receiver unit to lock said receiver unit in said received non-operative position.