open by pulling the middle out, and holding it right or left to open the opposing slot (one hand operation possible)
catch the cables for that slot and move the middle to the other side for the other slot.
press the middle down to lock.
When locked you can not remove the cables by pulling like with a clip - as the middle is now forced further down. But it requires only slight force to pull the middle open (quick release / panic snap).
mount
you can glue or screw (hole version) this onto a surface or power brick, but also keep free to loop redundant cable length. Or to keep different cables together.
capacity
slots can be used independently e.g. to keep usb and video in one and power in the other slot together.
1× power cables (8mm∅) per slot ⇒ 1 loop / 2 cables
2×shielded USB, video HDMI, ethernet or sat cable (4-5mm∅) per slot ⇒ up to 2 loops (1 per slot) or 4 cables
3× Bowden tubes (4mm∅)
5× USB / Audio / low power (3mm∅) per slot ⇒ up to 8 loops (4 per slot) or 10 cables
1× USB/Audio/cinch/RCA plug/jack per slot ⇒ 2 connector storage
or to keep drawstrings or filaments loosely in position