Synthrotek's 555 Timer Kit has endless usage! Use it as an LFO to modify existing noise making machines or use it as a stand alone tone generator or a clock. Adding this PCB to our PT2399 delay on pin 6 has been super awesome. (A MUST FOR CIRCUIT BENDERS) Many other ideas... Kit includes everything you need to make a variable pulse generator. Comes with 9V battery clip; use it stand alone or wire it up to your existing circuit.