Battery boxes protect batteries against impact, weather, gasoline, and oil. They hold batteries in place and contain leakage from damaged batteries. Boxes fit specific battery group size or multiple sizes and require adequate ventilation. The box may have a carry handle, or hold more than one battery. Tractor trailer and mobile home battery boxes may incorporate step plates or other vehicle exterior features. Other types of battery protection include battery hold downs and ground straps, protective battery caps and tubes, as well as battery monitors and surge protectors.