Long life and reliable operation is inherent in the design of the 201 series. The heavy duty welded carbon steel chamber provides a control to operate up to 1000 psi (69 bar) and process temperature up to 750°F (400°C), 400°F (205°C) at the electrical head assembly. The use of an external magnet reduces the possibility of magnetic particle build up inside the armature tube and subsequent loss of operation as may occur with the internal magnet repulsion design. Choice of construction provides equipment suitable for specific gravity as low as (0.60). Electrical requirements are met by use of hermetically sealed snap action or mercury switches in a variety of actions including SPST, SPDT, DPDT and DPST arrangements. Optional circuits are available for low current/voltage DC; high current DC; or high temperature applications. Standard process connections are combination 1″ NPT and 1″ socket weld hubs. Flanged connections are offered as an option.