Hermit crabs breathe through gills and are sensitive to changes in humidity, making it essential to maintain proper moisture levels in their enclosure. These sponges help support a healthy environment by assisting with humidity control. Simply place the sponge in your crab's water dish, allowing easy access to moisture. FeaturesColor: YellowMaterial: SpongeSize: 5.00 x 5.00 x 0.10 cm / 1.97 x 1.97 x 0.04 inSpecially designed to help maintain humidity in pet tanks or crab habitatsCan also be used as a cleaning sponge for everyday household tasksMade from safe, non-toxic materials suitable for use in pet environmentsEasy to use – place in the water dish so it occupies most of the surface areaPack of 12 sponges provides ample supply for regular use and replacement Package List 12 x Hermit Crab Sponges