Research Enterprises Limited (REL for short) was a short-lived Toronto-based Crown Corporation that built electronics and optical instruments during World War II. They existed only six years from late 1940 until 1946, and active only from late 1941, but during that period they became Leaside's largest employer, producing C$220 million worth of radar systems and optical instruments ($3,206 million in 2021). After the war, the government rapidly closed the various wartime companies it had started. After REL was closed, their factories formed the basis of a Corning Glass plant, Philips Electronics, and a variety of other firms. Today only a few of the original buildings still stand, used primarily for light industrial and small commercial enterprises.