The Walchem WPH310-141 controller is now obsolete and the closest equivalent is the WPH600 controller. The new WPH600 series has upgraded features; for reference, here is the description of the old model:
on/off control outputs, 120 VAC, pre-wired with 6” pigtails (wph410) or with 10’ cables (wph420), single isolated analog (4-20 mA) output, preamplifier (190783) w/10’ cable, pre-wired
