Thon Case Partition Kit 30x30

Perhaps just a little pricey but the quality of this is more that OK.

Mind when you drill the holes from the inside out to put a piece of wood on the outer surface and drill downwards, so you drill into that wood.
This is to prevent that the outer protection layer of the case gets too splintered. Otherwise the pop nails might not cover the damaged wood. With a wood block is goes well.

Also plan firts were to put the nails, there might be too less otherwise.