The ES-5 is an expansion module for the Expert Sleepers ES-3 Lightpipe/CV Interface, ES-8 USB Audio Interface or ES-9 USB Audio Interface.

It piggybacks on one of the host module's stereo channels to provide eight gate/clock/sync/MIDI outputs on the ES-5 itself, plus further expansion headers to connect up to six expansion modules e.g. the ESX-8GT Gate Expander, the ESX-8CV CV Expander or the ESX-8MD MIDI/DINsync Expander.