The Mosfet series was Tekin´s second generation of electronic speedcontrols introduced in 1988. This new Mosfet series had improved electronics, smaller case and a control LED for indicating full throttle position at setup. This series also was available with red or black coloured case.
Overall these versions were available
ESC-130 Racer (R) as budget version
ESC-170 Pro (P) as competition series
ESC-200 Pro X (PX) same as Pro but 3 wire setup for improved efficiency