Point Relief 11-1205 Moist Heat Pack to Ease Aches and Pains from arthritis, back pain, Circular, 10" Diameter

I had a partial knee replacement 4 years ago and used these in therapy. Well just had a whole knee replacement on other knee so bought these and the Chattanooga E-2 Hydroculator, glass I got Relief Pak first, because ones that came with Hydroculator from Chattanooga are stiff and hard, those went in box and stowed. Fortunately I have several sizes of the Relief Paks and they are great. I've been reading reviews and it amazes me how many people can't, won't or don't read directions, sad to give a bad review. I do understand if you don't have a Hydroculator, but I used a rectangular roasting pan with a rack in bottom to t o heat mine til I bought Hydroculator. I used a coffee/espresso temperature thermometer for temp. You don't boil it the first time. You put it in a pan of water, make sure you set something on it to keep it submerged for two hours, then it's ready to heat for its first use. Heating time on stove is about 30 min.