Large planter / "access box" (Moortown LS17)

Hi, if anyone can make use of this you're welcome to it and will save it going to landfill!

 I'm not exactly sure what it is, I think it might be for underground drainage?

It says "access box" on it but you could, for example, use it as a planter to restrict root growth on a large plant / small tree.

The internal measurement of the box is 45 cm x 45cm but the external measurement is more like 53cm x 53xm. Height is 32cm.

Very sturdy black plastic. A bit muddy as been stored outside in the garden (see photos)

Thanks