Critical to its quality and reliability is its glass to metal hermetic seal, where the glass and metal used must have exact linear thermal coefficients of expansion. Otherwise, cracking and poor seals will result. Like semiconductors, any foreign particles present in the manufacture will give rise to losses, quality and reliability problems. A highly precise and controlled laser sealing process is used to melt and form the glass hermetic seal, during which the air is removed and the glass is filled with an inert gas made up of mainly nitrogen. The glass is then annealed whereby removing any residual stress from the glass structure. A vacuum process is also used to achieve high voltage switching up to 1000 volts. Although a Reed Switch consists of relatively few components: Extreme cleanliness and high precision are a must for the manufacturing of Reed Switches and therefore the whole process is carried out in a clean room environment.