Three tall format nest and stack fish boxes (Llanystumdwy LL52)

Outside measurements: 800 L, 470 W, 300 D (mm)
Inside measurements: 700 L, 420 W, 290 D (260 mm deep to fill level)
Calculated capacity to fill level: 76 L.
Weight. 4kg. Many drain holes.
Washed up on Llanystumdwy beach.