This is a great two pack! I use these for my arms (both at the same time) and also used them linked together for my abdomen and back after my hysterectomy. The velcro straps link together and then you have a nice long wrap!They do smell funny when you use the microwave to heat them up. Not horrible, but funny. My kids did the running back and forth warming them up and they complained they smelled bad. I suppose every microwave is different so that could be why the 60 seocnds recommended for heating up wasn't really adequate. We did them together standing up on their sides curled around so that there was air movement all around. And it was usually acummulated time of 2.5 to 3 minutes to get them good and hot.I have not used them as a cold pack. Cold is not helpful for my nerve injuries in my arms. I do recommend them for heat packs! Very easy to use.