Monster Power Rockin' Roller Mini The Monster Power Rockin' Roller Mini is a portable speaker with a built-in rechargeable battery. It has a ruggedized housing and a carrying handle, making it easy to take with you wherever you go. The speaker has a variety of input options, including Bluetooth, AUX, and USB, so you can connect it to your favorite music sources. It also has a built-in FM radio and a microphone input, so you can use it to listen to music, make announcements, or sing karaoke. The speaker has a powerful sound and a long battery life, making it perfect for parties, picnics, or any other outdoor activity.