RadioShack 10W Handheld Powerhorn with Detachable Microphone Detachable Microphone - So you don't have to hold the entire powerhorn's weight in your hand. Build-In Siren - Provides a loud alarm sound. Requires 8 C batteries - Not Included Rust-Proof, Water Resistant Plastic Housing - For use in all weather conditions. Lock Bar - Lets you set the powerhorn so you can speak for a long time without having to hold the TALK bar.