In a cash transaction, Photonic Products Group Inc. (PPGI) of Northvale, N.J., has purchased the stock of MRC Precision Metal Optics Inc. of Sarasota, Fla. It will retain the company's work force, including its founder and president, Frank Montone. The acquired company will operate from its current location as a wholly owned subsidiary with the name MRC Precision Optics Inc., a PPGI company. MRC's expertise in manufacturing precision metal optics and optical assemblies complements the parent company's laser optics and Inrad optical component lines.