BET (Biotechnia Ellinikon Trikyklon) was founded by Petros Konstantinou in Athens, Greece, initially converting motorcycles into three-wheelers from the early 1940s. The company ceased production in 1975.
In 1965 it built a five-seat passenger car powered by a BMW 125cc motorcycle engine, of which only one unit was produced due to parts-availability problems, followed by a series of three-wheeler trucks. In 1973 it introduced the Model 500, a small five-seat car with a metal body and a Fiat 500cc engine, certified for production; 15 units were built, some of which survived for decades. Discussions with a South African company over exports or technology transfer were never realized.