Cars with pot-like containers are used to transport acids and other corrosive liquids, and these pots are set up on the car's frame. The pots are protected again tipping over and sliding by a sturdy, type of framework mounting with appropriate components to hold the pots in place. The cars' floors have slopes from the middle of the cars to both sides to draw off any overflowing contents. The cars are equipped with a handbrake that is operated from a brakeman's platform; cars with a brakeman's cab are possible but not mandatory. The pots are made of earthenware, a material that withstands even the strongest acids. These pots standing on the cars - usually eight to twelve pots each with a volume of 800 to 1,200 liters / about 211 to 317 gallons - are loaded with air pressure. Each pot has two connections for this: one marked in blue for blowing in air, and one marked in red for drawing out the load. The acid cars must be specially handled by the railroads, since the earthenware pots are delicate; in the event of damage, the contents flowing out can cause accidents. Acid cars are not maintained by the railroads; they are the property of the users, such as chemical companies, or they belong to car leasing companies such as Eva or VTG.