The Walchem WCT400-141N series controller is now obsolete and has been replaced by the WCT600 series controller. The new series has upgraded features; for reference, here is the description of the old series:
Bleed & feed, 120 VAC, prewired, isolated 4-20 mA output, graphite electrode & tee , 20 ft cable (for in-line or submersion mounting)
