Have two sets of them Purple is cheaper and a bit larger (I colored them black with fabric spray and fabric marker).Black looks better,costs more and is a tiny bit smaller. They are coolers and WILL hold a case of beer,plus keep it cool .Great for cold/frozen groceries .
I ride with a stainless steel water bottle.I freeze about 1/2 full of water, then, top it off for longer periods of being out.Keeps cold most of day and is like an ice pack for food/groceries.
I use the smaller ones in my full-sized leather saddlebags as a type of liner . They are 100% waterproof...leather is water resistant , so I know it will keep gloves,sunglasses,extra clothing, etc. dry .
I don't think you can go wrong with them. I've been impressed .