Product review (4 stars): Warning - Centigrade ONLY dispaly - no Fahrenheit - but pretty accurate.
The #1 issue is that this is CENTIGRADE ONLY.  There is no way to get a Fahrenheit display of the temperature. Accurate enough for such an inexpensive item. All three that I bought tested to within .5C of each other.  My freezer runs at approx. 0 F according to other thermometers that I have - these three show it to be at 1 F to 1.5 F

They are actually designed to snap into some sort of housing for a flush mount appearance.  I simply used some double sided tape to place it in the desired location, and snaked the sufficiently long enough wire and probe into the freezer.

NOTE  3-4 weeks shipping time from China - but the shipping was free even if you only ordered one of them. No $35 aggregate was needed!