National Technical Systems Inc. on Tuesday said that it has acquired Garwood Laboratories, a Pico Rivera product certification laboratory, for an undisclosed amount.

Garwood, which will operate as a wholly-owned subsidiary of Calabasas-based NTS, also has facilities in San Clemente. NTS Chief Executive William McGinnis said the deal increases its market share and adds several new clients in the aerospace, defense, telecom and commercial electronics markets.

“Garwood offers us a natural fit in terms of synergies with customers and services and will enable us to extend our reach throughout the Southern California region, which is a key geographical area for us,” said McGinnis in a statement.

Garwood is NTS’s third acquisition in the past year. The company bought Lightning Technologies Inc., a Massachusetts engineering services and testing laboratory, in September and Ingenium Testing, an Illinois provider of product compliance and engineering services, in July.

Shares were down 14 cents, or 2.6 percent, to $5.38 in midday trading on the Nasdaq.