ES-13    High Reliability Sound Actuated Relay 
 (DC 9V)   (relay contact : 2A)

Clap your hands & this little circuit will energizes / de-energizes a miniature relay.  Operates in the bi-stable or toggle mode.  An active high-pass filter (IC1B) filters out ambient noise so that the circuit is sensitive only to hand-clapping sound. 

Applications : 
sound activated table lamp, . . .