DIY Remote Control Doorbell Kit Electronic Parts Assembly Teaching Training ComponentsDescription:- The emission part of this kit uses transistor multi harmonic oscillator、 pulse modulated emission and quartz crystal frequency stabilization technology、 has the features   of long emission distance、 working stably and low static power consumption.- The emission part's power supply uses 12V battery (included)、 and the receiving part uses two AA battery (not included) to supply power.Note:AA battery is not included、 please note about it before you buy it.You can find the 12V battery inside the doorbell shell.Package included:1 !#!amp!*!times; Remote Control Doorbell Kit1 !#!amp!*!times; 12V Battery