If cost is the most important factor but something like a digital display is still wanted, the E5CSV is Omron’s most cost-effective temperature control product supporting both relay outputs and voltage outputs for solid state relays in a 1/16th DIN panel cutout. It has a single display, switching between current temperature and desired temperature. It comes with up to two alarms per unit, accepts either AC or DC voltage input, comes in grey or black and accepts platinum resistance thermometers and thermocouples. It also comes with Omron’s 2-PID adaptive control.