Features 1、With AUX + for Bluetooth audio input, subwoofer + left and right channel output 2、The power amplifier chip has AM interference suppression function 3、The protection mechanism includes overvoltage, undervoltage, overheating, DC detection, and short circuit protection, which is relatively safe 4、Using high&#8209;quality materials, strong and durable, has a long service life 5、With small size, easy to carry and store, convenient to use and with good performance Specification Item Type: Power Amplifier Board Product Model: ZK-TB21 for Bluetooth Version: 5.0 (Unobstructed: Approx. 10meter / 32.8ft) Input Sensitivity: 500mV Input Method: AUX+ for Bluetooth Number of Channels: 2.1 channels Power Amplifier Chip: TPA3116D2 (with AM interference suppression function) Adapted Speakers: 20-100W, 4-8Ω Output Power: Left and right channels <50W Subwoofer <100W Protection Mechanism: Overvoltage, undervoltage, overheating, DC detection, short circuit protection Package List 1 x Power Amplifier Chip 2 x Power Amplifier Board Module 1 x Screw Accessories Pack 1 x Screwdriver Accessories Pack