Zealot MT01M Retro Card Portable Wireless Bluetooth Speaker with Microphone(Black)1. Cinema level loud volume, no compromise on sound quality, suitable for a variety of scenarios 2. Built in dynamic loudness helps to adjust the sound tone balance, full sense of space 3. Super long battery life, say goodbye to anxiety 4. Stronger signal penetration, lower power consumption, faster and more stable connection, and wide compatibility 5. Supports wireless connection of two speakers, independent output of left and right channels 6.