The one-in 4-out MIDI thru box from MIDI Solutions sends all messages from the input to all 4 outputs. Active circuitry cleans up any skewing of MIDI data bits occurring at the input, ensuring reliable operation in setups that require daisy-chaining or long cable runs. The MIDI Solutions Quadra Thru is MIDI-powered and requires no batteries or power supply. A MIDI indicator LED lights up when powered, and flashes as MIDI data passes through..