GT Solar International, Inc., through its subsidiaries, is a provider of specialized manufacturing equipment and services essential for the production of photovoltaic wafers, cells and modules and polysilicon. Its principal products are directional solidification systems (DSS) units, and chemical vapor deposition (CVD) reactors and related equipment. DSS units are specialized furnaces used to melt polysilicon and cast multicrystalline ingots, from which solar wafers are made. CVD reactors are used to react gases at high temperatures and pressures to produce polysilicon, the key raw material used in solar cells. Its customers include several of the world's largest solar companies, as well as companies in the chemical industry. The Company operates through two segments: photovoltaic business and polysilicon business.