I keep it the freezer :)
My friend got one of these and I liked hers, so I got same one.  Seems to be of good quality.  There are ones out there that are lots cheaper.  Not sure if they are same quality as this one.  I went with this one because I knew what I was getting.  I keep it in the freezer and roll it on my face to refresh myself.  Helps with headaches too.
Rating: 4 stars