Glass top freezers are found primarily near the entrances of convenience stores and display frozen treats to tempt customers. The overall width and location of the air vents are important purchasing and placement considerations. The width of the unit will determine the overall storage capacity (cubic feet) and where you can actually place the unit in your establishment. If the model does is too wide for the space in which you want to put it, you will need to look for a narrower unit. Also, look at where the air vents are placed on the unit. The air vents indicate where the circulation is most important. You will want to give about six inches of clearance on the entire side on which the vent is located. The vent is important for removing hot air from the compressor motor, and blocking it means the unit will work too hard and may break down.