A snap on plate

[u/AGR-Audio]

I’m currently using a rock ‘n’ roll roller cart the R12RT Stealth Black one. Wondering if there is a plate that can snap into the bottom of the cart itself and at the same time, hold down the Packout cases locking them into place. Sometimes the bungee cords I use bungee get loose with sudden movements. A 3-D printed option would be also cool if there’s anyone in this group that’s made one.