Castech Inc. is principally engaged in the research, development, manufacture and sale of photoelectronic crystal materials. The Company's major products include nonlinear optics (NLO) crystals, such as lithium borate (LBO), beta-barium borate (BBO) and potassium titanyl phosphate (KTP); laser crystal components, such as neodymium doped yttrium orthovanadate (Nd:YVO4). The Company also provides optical filters, laser components and infrared (IR) optics products. The Company's laser components include oven and temperature controllers and BBO Q-switches. The Company's IR optics products include germanium (Ge), silicon (Si), zinc sulfide (ZnS), zinc selenide (ZnSe) and sapphire. The Company's products are used in laser and optical communication industries.