Features: Support multi-protect, over-heat protect, over-current,short-circuit protect. Bluetooth-compatible 5.1 version, the transmission efficiency is higher and more stable; With AUX, Bluetooth-compatible, USB,and USB sound card multiple audio input methods. It is recommended to equip 8 horn to supply DC9-24v without overpressure; If the 4 horn is driven, the power supply cannot exceed 12V; Specifications: Material:Metal Model:YS-LT21 Input Mode: Bluetooth-compatible / AUX/USB/USB Sound Card Work Voltage: DC9V-24V/3A Channel:2.1-Channel Bluetooth-compatible Version: Bluetooth-compatible 5.1 MAX Power Output:15Wx2+30W Match Speaker: 10W-50W/4-8 Note: Please allow 1-2cm errors due to manual measurement,please make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1set Bluetooth-compatible Power Amplifier