Many of the refrigerators have glass doors. Due to the quality of the construction, the cold air is not lost through the glass though, and you can be sure that the specimens, vaccines, or other items that you place within refrigerator will remain at the correct temperature. The unit will contain shelving, and the number and size of the shelves will differ based on the particular model and size of the unit. They will also have controls so you can set the temperature to exactly what you need. Some of the refrigerators will have different temperature ranges, as well as a different number of doors. It’s also possible that some will have a sensor system and alarm monitoring, as well as internal lighting, although this is not the case with all of the models.