These relays use electromagnetic coils to pull steel sleeves inside hermetically sealed containers. Hence the UO pellets are contained in zirconium alloy tubes with both ends hermetically sealed. The Nulka consists of the missile itself enclosed in a hermetically sealed canister. Nespresso's hermetically sealed capsules are made of Aluminum. Each assembly consists of 126 fuel rods with a hermetically sealed fuel. Potato sticks were originally packed in hermetically sealed steel cans. The primary function of the vacuum vessel is to provide a hermetically sealed plasma container. The pressure is achieved by simply applying heat to the hermetically sealed vessel. The pumps are the largest hermetically sealed pumps used in a nuclear reactor. To conserve water, a hermetically sealed water system was used. They can be used in configurations such as operations involving hermetically sealed barriers. In 2003, they were moved to new glass cases hermetically sealed with argon. Also they use a single hermetically sealed lithium iodide (LiI) cell as the battery. The watch features a hermetically sealed case which provided optimal protection for the movement. Magic spells to protect objects, for example, are the origin of the expression "hermetically sealed".