Pros: stays cold for very long time, large enough for knees and flexible enough for ankles
Cons: difficult to start chemical reaction
I have chronic problems with my ankles and knees. While a combination of footwear, inserts, and exercises has significantly limited the number of actual sprains and other injuries I suffer, I still get random joint pain sometimes accompanied by swelling or stiffness. These episodes don't last very long, but while they're in progress they can get very unpleasant and, at their most severe, limit my mobility. Ice almost always helps, but ice is also often hard to come by when I'm out and about. Enter the Ace Instant Cold Compress.
An inexpensive portable single use ice pack, the Ace Instant Cold Compress is small enough to easily stick into a backpack or desk drawer, cheap enough that you don't feel like you're wasting money when you use it, and cold enough to actually help joint pain. The last point is the important one as most of the other instant ice packs I've tried either do not get cold enough to be effective or warm up so quickly that the cold isn't applied long enough to help. Not so the Ace Instant Cold Compress. It gets to just about the perfect temperature - cold enough to really feel cold but not so cold it can't be held or touched or placed directly on the skin - and stays there for over an hour. Further, it remains cool enough to provide some relief for over a day beyond that, something I wouldn't believe if I hadn't experienced it for myself.
Unfortunately, triggering that cold is more difficult than it should be. While all instant ice packs use the same mechanism (two chemicals kept separate in the dormant state are combined to trigger the cold), the bubble you need to burst to allow the chemicals to interact is extremely difficult to break. It takes 4-5 minutes or more to activate the ice pack. Also, you're supposed to hear a distinct pop when the inside barrier breaks, but I've only been able to tell the pack is activated when it gets cold. The good news is that it takes mere seconds to get from room temperature to full cold so once you feel the pack get cold it's ready to use immediately.
The pack is large enough to provide decent coverage of knees and flexible enough to wrap around an ankle (with the help of gauze or an ace bandage). That, too, is a bit unusual for instant cold packs. Usually they're either a reasonable size or reasonably flexible but not both. It's very nice to find a solution that provides both and thus can be effectively used for both knee and ankle pain.
Sold for $1 a piece, the Ace Instant Cold Compress is inexpensive enough that anyone can afford to keep several around. I mentioned above that they fit into a backpack or a desk drawer and I have one stored in both my backpack and my desk drawer at work. Unfortunately, while they're more compact than just about any other instant ice pack I've used and come with a bare minimum of packaging, the chemicals within create a bit of a bulge so they won't easily fit into a purse or compact first aid kit. This is just an inherent drawback of the chemical system used to create the cold; the ice packs I've used that do fit in a first aid kit are much too small to be effective on a real joint.
The Ace Instant Cold Compress isn't perfect. For one thing, it takes an extreme effort to activate the chemical reaction. However, it's by far the best instant cold pack I've ever used. It's large enough to effectively treat knees, flexible enough to wrap around an ankle, cold enough to help without being too cold to touch, and remains effective far longer than any other ice pack I've tried. If you have any trouble with joint pain or if you want to pack a cold treatment on a camping trip or athletic outing, the Ace Instant Cold Compress is a good choice.