Metal bellows mechanical seal has a very wide field of application, but because of high price we use it for extreme conditions, like very high temperature, aggressive and dirty media. Main advantage is that there is no dynamic O-ring or elastomer part. All elastomer parts have a high temperature usage limit, and when it is passed, mechanical seal failed. Metal bellow mechanical seals work in high temperature, high aggressive and high viscosity media without fail. Because of metal bellows design, seal could work with media containing solids. Independent of direction of rotation.