Clothing or Tent/Parka toggle, like a button but long and designed for cord.

30mm long x 9mm wide x 4mm thick

Holes in the toggle are designed to allow the use of standard military issue parachute cord.

I have a Soviet surplus tent half that also converts into a parka/rain cloak that had all its toggles pop off so I decided to make my own and breathe new life into the thing. The toggles are also wide enough to reliably secure most stand sized grommets on tarps and tents.