This is PERFECT to transport my Mom's insulin pens (Humulin-N KwikPen) when we travel. There's plenty of room to store up to 4 pens or fewer pens plus other medication she uses that requires refrigeration. The case is a good size (5-4/5" x 8-4/5") and fits nicely into a purse or briefcase (or REALLY LARGE pocket). It's completely enclosed with a zipper than opens/closes from both ends (2 zipper pulls). The inside mesh pocket (in front of the insulated pocket that holds the HOT/COLD gel pack) is held shut with a 1.5" strip of velcro at center pocket. The external zippered mesh pocket is just a tad bit smaller (due to stitching) than the external dimensions, with ample room to hold extra pen needles, alcohol swabs, or other items. With 4 KwikPens in it, the case closes easily; plenty of room to hold other items provided they're not too thick. The gel pack is a HOT/COLD pak, with instructions on how to how best to freeze (x 2-3 hrs) or heat (10 seconds intervals in microwave until it's hot enough, but not too hot that you'll burn yourself). My only complaint is that the gel pak, when frozen, must be pushed into the pocket (gently) to zip close. I imagine you'll have to be careful when opening the case to make sure the frozen gel pack doesn't fall out (I'll mark TOP to indicate which way is up to avoid the pack falling out when I open it). Other than the frozen gel pack issue, this medicine cool (or heated) travel case is PERFECT!! Well constructed, plenty of storage, completely closable with 2-pull zipper, and great value. Would recommend this highly to anyone!