I purchased the large size hot/cold gel pack to ease the pain of carpal tunnel in my hand/arm. The relief was immediate with this product. I placed it in the freezer for about 5 minutes then wrapped it around my hand and lower arm. The velcro straps kept it in place. The coldness was so soothing. The soft fabric covering the gel pack was so comfortable on my arm. It helped reduce some of the swelling I was experiencing in fingers and hand. I used the gel pack in addition to the medication prescribed by my doctor. The gel pack helped relieve discomfort while the medication did its work. This gel pack can be used on other body parts. It's perfect for a knee. It can be placed across the back or neck or shoulder.