hi I have the same problem I have 13 grand kids I am making them there own rice packs they love them .I buy fun fabric and make the sack put white rice in. sew it up and there you have it the kids or parent put them in the microwave for 2 minutes and now they can be nice and warm.mygrand kids love taking them to bed I love them for neck ach or leg cramps give it a try if you need measurements let me know have a good day