The HK1521 stereo LED VU meter is designed for visual indication of audio signal levels for left and right channels. It is built using two KA2284 (AN6884) integrated circuits, with each IC driving a 6-LED bar display.
The device features two inputs - one for the left channel and one for the right channel. The input signal is low-level, typically around 0.750 V. The VU meter is not intended for direct connection to a loudspeaker output and operates with signal levels in the approximate range of 0.5 to 1 V.
The indication level is adjusted via a trimmer potentiometer. The display is logarithmic, with steps of -10 dB, -5 dB, 0 dB, +3 dB, and +6 dB.
The supply voltage range is 5 to 15 V DC. The printed circuit board dimensions are 104 x 34 mm.

Technical Specifications:
Application: audio equipment, audio level indication.
Integrated circuits: KA2284 / AN6884.
Channels: 2 (stereo).
LEDs: 2 x 6.
Indication type: logarithmic.
Indication levels: -10 dB, -5 dB, 0 dB, +3 dB, +6 dB.
Input level: approximately 0.5 - 1 V (standard 0.750 V).
Level adjustment: trimmer potentiometer.
Output current: approximately 15 mA.
Supply voltage: 5 - 15 V DC.
PCB dimensions: 104 x 34 mm.

This product is a fully assembled module.
It is also available as a DIY assembly kit - Product code 1011 (separate product).