This piece of equipment is highly useful! Though it isn’t necessary life is much easier with a carboy dryer.
The carboy dryer is made of a high quality food grade plastic. There are strategically placed holes and risers to allow airflow around and inside the carboy. The carboy is washed and sanitized as you normally would and then placed upside down on the dryer to air dry.
As I said, the dryer is not necessary but I highly recommend it. When I first started using carboys, I would clean the container and leave it upside down in the sink until it dried. This works well but takes up a lot of space in the sink.
Your sink is useless until the carboy finishes drying.
Using the dryer allows you to move the carboy to some other location while drying, a counter, a table or back into the brew closet.
I usually put handles on our carboys; I mentioned these in an earlier post. You can review the post here. I leave these handles on the carboy and that can make it difficult to balance on the dryer. This is why I use the dryer in my brew closet; I can lean the carboy in the corner to help stabilize it.