Outdoor Tech OT4200 Big Turtle Shell - Ultra Loud Rugged Bluetooth 4.0 Wireless Boombox & Powerbank (Black) The Big Turtle Shell provides a full wireless audio experience using Bluetooth 4.0, which connects to most audio devices, bringing you 110 decibels of auditory bliss. Rugged and water resistant to IPX-5 standards the Big Turtle Shell is the loudest, toughest and best looking Bluetooth speaker on the market. Internal powerful and rechargeable Lithium Ion battery gives you 16 hours of party time as well as serves as a backup power bank for your other electronic devices. Portable as can be with strong handles for carrying, or mounting to things.Bluetooth range up to 30 feet from device An integrated microphone along with external controls to adjust volume and tracks, allows you to be a "Master of the Universe", minus all the bulging muscles and weird swords, spells and such. Refer to the PDF attached below in Technical Specification for User Manual.