MAVERICK - Amplifier-equipped box subwoofer (20cm)

Maverick 20cm subwoofer box with built-in amplifier. Model name and output details are unknown. Box size (actual measurement, excluding protrusions): Width 48cm x Height 26cm x Depth 25cm. Supports speaker input (high input) and RCA input. Power on and sound output have been confirmed. Noise occurs when adjusting the gain. Output seems unstable at high volume. There are scratches and stains that cannot be removed. Please pay attention to the condition and details before purchasing.