I like having both the current temperature display along with the set temperature display. And it's also nice to have the temperatures displayed in degrees Fahrenheit. Operation is a bit counter-intuitive.

Works as advertised, very easy to program and clear display, would prefer the 4 circuit connectors to be bigger, but that's not a deal breaker. So far very appy with purchase.

Using this to control an exaust fan mounted to the lid of my DIY solar generator. It's programmed to kick the 80mm fan on once the temperature reaches 85⁰. I then programmed a 2⁰ "dead band" so it doesn't continue cycling on and off.I then tested it several times by just holding the temperature probe in my hand. The digital guage shows the temp climbing and as soon as it hits the setpoint the relay kicks on and the fan starts spinning. Really neat and well designed gadget for the price.I will most likely get a second one to control some silicone heating pads to keep the Lifepo4 battery above freezing for winter use. In this case the unit will control a relay to send power to the heating pads vs running them right off the controller like I did with the fan.

I am using this for a small greenhouse and it works great. This is what I used...From Bastrop Guardian review:===============================Technical Specifications:-------------------------------Controller Power: .05VDC to 12VDCController Maximum Amperage: 20 AmpsControlled Device Votage: "0 to 14VDC" and "0 to 125VAC"Refresh rate: Approximately 0.5S SecondsController Draw: 150mA to 0.01 ampsNote: I use this in my RV with Lithium Batters (14.4 Volts) and "So Far" - No Problems===============================Features:-------------------------------Modes: Cooling and HeatingLED Display: Red & Blue.Temperature Range: -58 to +257 Degrees FarenheitResolution: -3.9 ~ 99.9 Degrees FarenheitAccuracy: 1 Degree FarenheitBacklash Accuracy: 0.1 Degree FarenheitMemory: Retains its Settings after a "Power Disconnect"===============================Light Indications:-------------------------------"Lights On" = Your Controlled Device is On"Lights Off" = Your Controlled Device is OffTrouble Codes (Will Automatically "Power Off"):1 = Sensor Missing or Damanged2 = High Temperature Protection3 = Low Temperature Protection===============================Connectors:GND = 12VDC Power "Ground"VCC = 12VDC Power "Hot"KO = To DeviceK1 = From SourceNote: This Device "Closes" [Dead Switch] Connector K0 (to Device) and K1 (from Source) when Activated (Passes Current [or Ground] "from" K1 "to" K0 to) your Controlled Device.Recommendation:If you are using a Device that Requires more than 20 Amps (or maybe "always" Regardless of Device Amperage Need), you may want to Use a Relay between this Controller and your Device - Using this Controller to "Trigger" your Relay and using the Relay to Power your Device. I always use a Relay for "All" my VDC Devices.Relay: https://www.amazon.com/gp/product/B000P61E36/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1Relay Connector: https://www.amazon.com/gp/product/B001B801W2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1===============================Parameter Setting Instructions:-------------------------------"Set" Button:This Button will Allow you to:A) Enter the Temperature SettingB) Enter the Six Different Parameter Settings (Below)-----------------------------------------------Setting the Temperature and Parameter Settings:on the Screen you want to Set/Change:A) Use the "+" Button to Increase the Value of the ParameterB) Use the "-" Button to Decrease the Value of the ParameterC) Press the "Set" Button once you Achieve your Desired Parameter Setting to Set-------------------------------Parameter "P0" (Default "C" [Cooling]) / Temperature Default: 60 DegreesChooses between Heating or Cooling (H/C).Once the Temperature Probe senses the "Set Temperature", the Relay Turns Off your Controlled Device.Important: See Parameter "P1" Below.-------------------------------Parameter "P1" - (Default "2 Degrees"):Sets the Temperature "spread" between turning on your Controlled Device on and turning it off.Example:A) The relay will turn Off your Controlled Device when it Reaches "Set Temperature" (Parameter "P0" above)B) When the Temperature reaches "Set Temperature Spread Degrees +/- the Temperature Setting (Parameter "P0" above [H/C])", it will turn on your Controlled Device.Note: Increasing the "Spread" can keep your Controlled Device from turning On and Off too Often.-------------------------------Parameter "P2" (Default "0 Degrees"):Temperature correction. Adjusts the Temperature the Probe is sensing if it is not reading correctly.Recommendation: Leave it at Default unless you are Certain there is a Temperature Reading Variance.-------------------------------Parameter "P3" (Default "Off"):Adjusts "How Many Minutes" your Controlled Device Stays On within the "Temperature Parameters" (Parameters "P0" + "P1" Above).Note 1: Your Controlled Device will Continue to "Stay Off". Press the "Set Button" to Reset.Note 2: Only Needed if you Determine your Controlled Device is Staying On too long.-------------------------------Parameter "P4" (Default "Off"):Adjusts "How Many Minutes" your Controlled Device Stays Off within the "Temperature Parameters" (Parameters "P0" + "P1" Above).Note 1: Your Controlled Device will Continue to "Stay On". Press the "Set Button" Repeatedly to Reset.Note 2: Only Needed if you Determine your Controlled Device is Staying Off too long.-------------------------------Parameter "P5" (Default "Off")A) "On" Locks your Chosen Parameter Settings.B) "Off" Unlocks your Chosen Parameter Settings for when you'd like to Update them.

Using "David's Review/Instructions" (a Great One) - and other Reviews - and the Seller's Information, I have Compiled a "Complete Instruction Booklet" (w/o Pictures) for the "Average User". Please let me know if I got anything Incorrect.Of Course, you can Copy and Paste this into a "Text Document" to Save on your Computer for Future Use if you'd like. :-)===============================Technical Specifications:------------------------------- Controller Power: .05VDC to 12VDCController Maximum Amperage: 20 Amps Controlled Device Votage: "0 to 14VDC" and "0 to 125VAC" Refresh rate: Approximately 0.5S Seconds Controller Draw: 150mA to 0.01 ampsNote: I use this in my RV with Lithium Batters (14.4 Volts) and "So Far" - No Problems===============================Features:------------------------------- Modes: Cooling and Heating LED Display: Red & Blue.Temperature Range: -58 to +257 Degrees Farenheit Resolution: -3.9 ~ 99.9 Degrees Farenheit Accuracy: 1 Degree FarenheitBacklash Accuracy: 0.1 Degree Farenheit Memory: Retains its Settings after a "Power Disconnect"===============================Light Indications:-------------------------------"Lights On" = Your Controlled Device is On"Lights Off" = Your Controlled Device is OffTrouble Codes (Will Automatically "Power Off"):1 = Sensor Missing or Damanged2 = High Temperature Protection3 = Low Temperature Protection===============================Connectors:GND = 12VDC Power "Ground"VCC = 12VDC Power "Hot"KO = To DeviceK1 = From SourceNote: This Device "Closes" [Dead Switch] Connector K0 (to Device) and K1 (from Source) when Activated (Passes Current [or Ground] "from" K1 "to" K0 to) your Controlled Device.Recommendation:If you are using a Device that Requires more than 20 Amps (or maybe "always" Regardless of Device Amperage Need), you may want to Use a Relay between this Controller and your Device - Using this Controller to "Trigger" your Relay and using the Relay to Power your Device. I always use a Relay for "All" my VDC Devices.Relay: https://www.amazon.com/gp/product/B000P61E36/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1Relay Connector: https://www.amazon.com/gp/product/B001B801W2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1===============================Parameter Setting Instructions:-------------------------------"Set" Button:This Button will Allow you to:A) Enter the Temperature SettingB) Enter the Six Different Parameter Settings (Below)-----------------------------------------------Setting the Temperature and Parameter Settings:on the Screen you want to Set/Change:A) Use the "+" Button to Increase the Value of the ParameterB) Use the "-" Button to Decrease the Value of the ParameterC) Press the "Set" Button once you Achieve your Desired Parameter Setting to Set-------------------------------Parameter "P0" (Default "C" [Cooling]) / Temperature Default: 60 DegreesChooses between Heating or Cooling (H/C).Once the Temperature Probe senses the "Set Temperature", the Relay Turns Off your Controlled Device.Important: See Parameter "P1" Below.-------------------------------Parameter "P1" - (Default "2 Degrees"):Sets the Temperature "spread" between turning on your Controlled Device on and turning it off.Example:A) The relay will turn Off your Controlled Device when it Reaches "Set Temperature" (Parameter "P0" above)B) When the Temperature reaches "Set Temperature Spread Degrees +/- the Temperature Setting (Parameter "P0" above [H/C])", it will turn on your Controlled Device.Note: Increasing the "Spread" can keep your Controlled Device from turning On and Off too Often.-------------------------------Parameter "P2" (Default "0 Degrees"):Temperature correction. Adjusts the Temperature the Probe is sensing if it is not reading correctly.Recommendation: Leave it at Default unless you are Certain there is a Temperature Reading Variance.-------------------------------Parameter "P3" (Default "Off"):Adjusts "How Many Minutes" your Controlled Device Stays On within the "Temperature Parameters" (Parameters "P0" + "P1" Above).Note 1: Your Controlled Device will Continue to "Stay Off". Press the "Set Button" to Reset.Note 2: Only Needed if you Determine your Controlled Device is Staying On too long.-------------------------------Parameter "P4" (Default "Off"):Adjusts "How Many Minutes" your Controlled Device Stays Off within the "Temperature Parameters" (Parameters "P0" + "P1" Above).Note 1: Your Controlled Device will Continue to "Stay On". Press the "Set Button" Repeatedly to Reset.Note 2: Only Needed if you Determine your Controlled Device is Staying Off too long.-------------------------------Parameter "P5" (Default "Off")A) "On" Locks your Chosen Parameter Settings.B) "Off" Unlocks your Chosen Parameter Settings for when you'd like to Update them.Recommendation: Locking is Recommended because The "Set Button" is very easy to bump into and it can change the set temperature quite easily.===============================I Hope you found this Helpful. And don't forget to let me know if I've "Missed Something" and/or "Got Something Wrong".Oh... And One More Thing... Please "Overlook" any Grammatical/Spelling Errors. :-)