noun
drying agent; desiccant
A substance that absorbs moisture, commonly found in food packaging or electronics to keep contents dry.
このお菓子の袋には乾燥剤が入っています。
There is a desiccant packet inside this snack bag.
カメラを湿気から守るために乾
I use a drying agent to protect the camera from humidity.
除湿剤 is a dehumidifying agent often used in rooms or closets, whereas 乾燥剤 is typically a small packet placed inside packaging.
Compound of 乾燥 (drying) + 剤 (agent, preparation).