Features: ZK502A is a portable audio amplifier module that features a timer shutdown function. It has a classicmechanical volume knob and supports multiple audio inputs such as AUX, BT5.1, Udisk, and USB sound card. It is suitable for anyone who wants toenhance their audio experience. It can be used in various scenarios such as home, office, or outdoor activities. The ZK502A is small and exquisite, making it easy to carry around. Specifications: Product Name: Digital Power Amplifier Board Supply Voltage: DC9-24V Output Power: LeftandRight Channel 50W+50W Model Number: ZK502A Channels: 2.0CH Size:approx 78x50x18mm/3.07x1.97x0.71in Material: Plastic BT5.1 (Unshielded 15M/49ft) Colour:Black Note: Only the above package content, other product not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 0-2cm. Package includes: 1Set x Amplifier Board