Rear support jacks for the off-road trailer — sold as a pair, which is how most people need them.

Rear jacks stabilise the trailer once it is unhitched. On a camping trailer that is not a nicety: without them the whole thing rocks on its suspension every time somebody moves inside or opens the tailgate.

A pair also lets you level the trailer side to side on uneven ground — the difference between sleeping flat and sleeping against one wall.

Buying the pair costs less than two individual jacks.