A variant of the extended version used in desert border patrol make use of a high @-@ ceilinged canopy to allow a swivelling rear @-@ facing heavy machine @-@ gun mount , while the canopy can be extended to provide a mobile command post . An air conditioned hardtop version of the extended model is often used by officers , and a version developed for riot control have clear polycarbonate shielding along the rear sides and roof , as well as gunports for less @-@ lethal weapons . The shielding allow for a wide field of view while at the same time protecting against firebombs and rock @-@ throwing .