We have had them almost too heavy to lift and stacked up to 8 high and still show no sign of being overloaded.

In the second picture above you will see two wooden strips. These serve a dual purpose as feet and as location bars which fit into the box below for stable stacking.

Each box has a folding steel handle at each end which are strong enough to take the weight of a box filled to the safe limit for a person to lift. In years of use in our workshop, we have never had a handle break, nor any other failure.

The boxes are 61 cm long (not including handles), 37 cm wide and 22 cm high (including feet). We calculate that the capacity is in excess of 45 litres.

We do not think these boxes are waterproof.