MegaMouth design with internal metal frame gives easy access to main compartment. Heavy-duty zipper closure. Quality stereo speaker system connects to your digital music player or smartphone. Speaker on/off switch. See-through cover helps easily identify selection and function of music player. Integrated tool bag cover helps keep audio components safe from dirt and debris. Ergonomic handle design is padded to reduce stress on hand and wrist. Adjustable padded shoulder strap for easy carrying. 18 multi-use inside pockets and 21 outside pockets help organize tools. Base pad feet help reduce wear and abrasion. Power via AC (alternating current) wall plug transformer or 4 D-cell batteries (not included).