The Dura Kold Knee Wrap, which I purchased and briefly used, consists of rows of individual hard ice cube-size lumps, when frozen, unlike the usual single flexible gel packs. It only flexes between each cube, but, the result is lumpy and not conforming. It's not something you want to throw on after exercise. Perhaps the hardness of each cube indicates it remains cold longer, but, I found it unacceptable overall.

I play tennis twice a week and have had several operations on my knees. My doctor recommends icing after playing. This is the best ice pack for icing! Also helps with shin splints. Covers the whole area. Thank you!

Keeps the cold temp for a long time. Use it on my knee and foot. Very durable quality product.

Big enough to wrap all around my knee and then some. It's cold.
Takes up quite a bit of room in the freezer. Let's see how the velcro holds up.

My knee is feeling much better since I use this every night