In this world nothing is certain but death and taxes -- and those things tested by MTS Systems. The company produces testing systems that simulate repeated or harsh conditions to determine mechanical behavior of materials, products, and structures. Its systems are used worldwide in infrastructure markets, from inspecting steel to locomotive rail testing. MTS caters to auto makers with road simulators. In aerospace, MTS tests aircraft fatigue. Services include maintenance and training. MTS also supplies industrial sensors (Temposonics) to increase machine efficiency and safety. About three-quarters of the company's customers operate outside the US.