This fun little sound generator is more than a siren. Once assembled you can create your choice of 4 different sound effects: Police siren, fire brigade, emergency vehicle, and laser gun! Use the laser gun to go on a rampage, and then just call in the police and fire vehicles to clean up your mess! Wow, how"s that for copywriting imagination! Variable pitch control allows you to customize the sound! Built-in PC board mounted speaker makes this kit ready to go when you"re done. Runs on a standard 9V battery (not included). Measures 2.4" x 1.6". From Velleman. (Did I say imagination?!)