Descrição The LGL Group is hoping that one isn't the loneliest number. Previously made up of two separate businesses, the company has a sole remaining line of business: its MtronPTI subsidiary. The subsidiary produces frequency control devices, such as crystals and oscillators, used primarily in communications equipment. MtronPTI was formed in the 2004 merger of M-tron Industries and Piezo Technology, Inc. In 2007 The LGL Group sold certain assets of its unprofitable Lynch Systems subsidiary for about $3 million. The company's sales are roughly split between the US and other countries.