Heating pad by Shuai & Mei Daily Products (Qingdao) Co., Ltd.
Heating pad has many names, such as shipping warmer, pet warmer and special warmer.
What's heating pad? https://www.warmerproducer.com/index.html
The details are as follows:
Size: 95x70 mm
Net weight : 17 g±2
Packing: 240 pieces/carton
Heating Last: 6+hours,
Average Temp: 40C
Max Temp: 45C
Material: Iron Powder, Water, Vermiculite, Activated Carbon and Salt.etc
Shelf Life: 3 years
Storage: Keep in dry, cool place and avoid direct sunlight
Its features: All natural ingredients
No batteries, no microwaves, no fuels.