Features for the Shuttle Bus PA Amplifier - Power Output: 70 watts - Power: 12 Volt - Installation: in-line between existing stereo and speakers - Electronics enclosed in small module that hides in dashboard - Automatically interrupts audio from stereo and engages microphone amplifier when keyed - Dimensions: 1.16"W x 1.7"H x 3.35"D A great way to add a public address (PA) system to your shuttle bus. We also sell the bus microphone. Please browse our Bus Parts Superstore for all of your shuttle bus parts needs. .