There are two types of loggers for your vaccine fridge: ones that sit inside the fridge and measure the temperature with a built-in sensor, and ones that sit outside the fridge and measure the temperature through a probe wire.
Only some fridges have the suitable probe wire – specifically the Medisafe range from Avem Quirks.
So which is better?
All types of LogTag are very similar in the ease of use and quality of reports.
The main difference with these two is that, because the external probe sits outside the fridge, it is easier to see the alerts.
And if you have the premium model with display, you also have the option of audible alerts.
Apart from that, there is no advantage to having one or the other.
Can I use an internal sensor model in a fridge with an external probe wire?
Of course. Internal sensors models can monitor any fridge or freezer. If you are replacing an obsolete logger with external probe, or your probe wire has been damaged, you can just get a LogTag with with an internal sensor (like the TRIX-16). Or, for a little bit more, you can get the TRID30-7R with LCD Display and replaceable battery. These LogTags will use the same Reader and the same software.