When I visited Bangnarmpheung Floating Market in Bangkok, a popular floating market among Thais, I found this item. It's a microwaveable neck warmer filled with wheat seeds. Pop it in the microwave for a minute or two and the heat is released slowly. I've seen this in the west used to warm people in winter, here in Thailand, they've packed them tightly into neck braces, and used with stretching exercises as part of a massage. You can see it in the video below.
This is an OTOP sponsored product, the one-tambon-one-product promotion agency that promotes regional arts and crafts.
The maker can be contacted on +66 (0) 84-0092266.