Logistic companies manage the movement of goods from a starting point, such as a factory or mine to the point where the product is used by the customer and companies. Many things are moved by logistic companies including precious and non-precious minerals, materials used in the manufacture of goods, food, animals, equipment and fluids such as liquids and gases. Many forms of fuel are moved by logistics companies including coal in trucks and petrol (gasoline) in road tankers. Oil and gas is transported by logistic companies in specially designed tankers that carry millions of tons of oil and gas from the point of production to the countries and customers all over the world, usually by sea. In the United Kingdom, even chocolate is carried by heated road tankers all over Great Britain. Logistic companies contribute a great deal to advancing civilisation by linking people to products. Logistic companies need to plan their activities very carefully to maximise their outreach as cheaply as possible but at the same time giving them sufficient profit. Courier companies such as Deutsche Post DAL, FedEx, TNT and Aerospeed Couriers are specialised logistic companies. One of the aspects of logistics that are important is managing warehouses and depots efficiently so that goods are turned around as quickly and efficiently as possible. Another important service provided by logistic companies is security. A warehouse can only be successful if goods do not disappear out of the back door. There are also third party logistic companies which are good at integrating logistic and other operations for a company. These logistics companies help their customers by outsourcing the skills of third parties. One of the advantages of using third party logistics companies is that they can be more flexible in designing the customer a focused system of integrated operations, including transport warehousing even for smaller customers. In some cases these third party logistics firms offer services that are not strictly logistics based on the customers’ special requirements.