Desiccant Canister Aluminum, 4" Long X 2.1" Wide X .57" Deep.

Compact, perforated canisters absorb moisture in glass jars, airtight cans, plastic pouches, and tool boxes. They contain silica gel that changes from blue to pink when absorption capacity is reached. Silica gel absorbs up to 21% of its weight in moisture at 40% relative humidity (RH). To reactivate, heat in a 300°F oven for three hours. 

Aluminum Canister— Has a window in the center to monitor color change.