Formula to extract a value, based on text selected from a drop down menu

Dears,
I am creating a excel calculator to quick and easy calculate CBM (cubic metres) for a total number of cartons and pallets loaded into a container.
The value of 1 carton or 1 pallet will be different depending on which type of packaging/pallet it is.

I have created drop down menues in order to choose the correct packaging / pallet.
But I am stuck on on to create the formula.

If I for example choose "LANDFROZEN 7KG CARTONS" from the drop down menu, I need the formula to collect the value in cell E18
If I for exampel choose "LANDFROZEN 10 KG CARTONS" from the drop dwon menu, I need the formula to collect the value in cell E25 .... and so on.

I have tried to use several functions, but none is working the way I want them to :-)

Does anyone have any idea what function/formula that would be the best to use?

I have enclosed my spreadsheet in case my explanation where not so easy to follow.