There are plans for two (2) different field boxes on my web page. One is very simple and basically just a box shaped to carry a can of fuel and a few tiols. The second is a more complex design but is intended to carry everything that you might need on the flight line and nothing more. The idea is to leave the items that are used for field repairs in the car until they are needed but still have all the items necessary for a day of flying right at your fingertips.