A few of us in here have been tinkering with the above - take your pick of suppliers !
Mine, and Gannons , I think, came with Chinglish destructions, so takes a bit to work them out.
They are made to fit in a rectangular hole of a panel so a rectangular hole saw would be an ideal extra

Designed to be able to switch something on or off with not supplied relay, can be set once instructions deciphered, to turn on with a rise or a drop in temp detected.
Also settable to trigger your relay 1 to 10 degrees C after the temp you set - something instructions call "backlash"
Tricky dudes could combine this with a few other control servers to make your own climate control in an old AC Brumby !
I have extended the sensor lead with simple old speaker wire - skinny stuff from chapy stereo as the lead supplied not long enough for my aquarium ( they are sold as aquarium controllers)
On first hook up I was monitoring the air temp changes around me, such a sensitive little sender and readout in 1/10ths of a Centigrade on display.
Also has delay time zero - 10 mins
The rear of the unit has block terminals for wires, seems to be ambidextrous for power hook up. I used the one of the two power terminals next to the switch terminals for earth so a wire link I made links between earth/vehicle ground of the units power supply and closest side of switching terminal gets the earth connection. From there my buzzer (or relay terminal 85) earth gets the other switch terminal for its earth supply while buzzer pos (relay 86) lead joins the units pos supply in the other pos power supply terminal I have nominated pos. Got it ?
Also has a pair of terminals that can be linked either via wire link or put in a nother switch - to lock out any setting changes by fumbling fingers !
Endless possibilities of tinkering with a temp unit so cheap...monitor LPG converters for freeze alert, indicating gas blockage or water loss ...make an anto theft device that requires sensor to hit say 108 C with aid of a match before car will start

Cheap as chips almost, could add one just for ambient air temp, another for intake air temp. I ran one on the EA82T alloy crossover to observe - forgotten data already

A mate could use one on his US clunkers diff that overheats and chatters up mountain climbs
