Boss released the HC-2 Hand Clapper in 1984 alongside the PC-2 Percussion Synthesizer. Both units are a little larger than a standard Boss pedal, have a battery compartment underneath (they run on a 9V battery) and jacks on the rear. The metal case sports controls on the top and a thick rubber trigger pad. There is also a 9V DC socket for use with an external power supply.

The HC-2 is a single-function hand clap synthesizer. It sounds similar to the TR-808/909 clap, and uses a variation on the same circuit. White noise is filtered and shaped, and here the user has some control over that—a Dry control determines the brightness of the sound (tone), and a Hall control determines the tail length (reverberation).

The unit can be used alone, with the sound being triggered by tapping the pad, or in conjunction with various drum machines or sequencers—a 1/4" input jack takes a positive trigger voltage pulse. The strength of the trigger, coupled with the Sensitivity control, determines the volume of the sound.

Simple in operation, the HC-2 is a useful addition to drum machines such as the DR-55 and TR-606, both of which have suitable trigger outputs and lack clap sounds themselves. It is also good fun to play manually, and varying tap strength can be used to good effect; rolls are also very easy to achieve when played using the fingers.