What is tank 500?

There is not enough information available to specifically identify "tank 500" as it could refer to a storage tank, a military tank, or some other type of tank.

If you are referring to a storage tank, it may be used for storing liquids or gases in various industries such as oil and gas, chemical processing, water treatment, or agriculture. The capacity of tank 500 would depend on its dimensions and design specifications.

If you are referring to a military tank, it could be an armored vehicle used for combat purposes. Tank 500 would likely be a designation for a specific model or variant of a tank used by a particular country's military.

Without more context, it is difficult to provide specific information about tank 500. It would be helpful to provide more details or clarification to better assist with providing information about what you are referring to.