The input voltage range of bluetooth audio amplifier board is dc 8-24v. Current entry: 2nd or above. Note: the input voltage should not be more than 26v, otherwise the audio amplifier module will be damaged. Two channel 10w/15w/20w amplifier board work with multiple speakers (4-16 ohm), supporting bluetooth stereo audio input. This bluetooth audio amplifier module comes with a protective shield, extremely protects the units from damaged, supporting reverse connection protection, short circuit protection and self-recovery overheat protection. Press gear pot to pause/play. Turn right to increase volume and turn left to decrease volume. Indicator light design helps you know the connection condition. Using the latest bluetooth 5.0 version, the distance between wireless bluetooth audio input and maximum receiving is 15m (no obstacles). Wide operating voltage range Suitable for many types of speakers Adjustment knob reverse polarity protection Short circuit protection Self-recovery overheat protection Bluetooth 5.0 Scope: Working voltage: DC 8v-24v Communication distance: 15 meters (maximum) Output power (1khz): Output power 16w*2 in 12v 4ohm Output power 10w*2 in 12v 8ohm Output power 15w * 2 in 16v 4ohm Output power 15w * 2 in 16v 4ohm Output power 20w*2 at 20v 4ohm Output power 30w*2 at 24v 4ohm (requires additional heat sink!) Matching speakers (30w~150v): 8v 12 4 ohms on 12v 8 ohm 8v 24 24v 16 Ohm 8v 24 24v Working temperature: -40Celsius~85Celsius Working humidity: 0% rh 95% rh Colour:black Material:abs+metal Size:50 x 35 x 14mm Package Contents: 2x Bluetooth 5.0 Amplificador Board Only the above package content, other products are not included. Note: Light 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 +/- 1-3cm.