When your pets urine touches the Wee Sponge powder, it solidifies into a gel, trapping liquids and airborne odors. The Pee Pod can hold about 2 liters of liquid. Simply throw out the pod and replace it with a new one every few days. Pee Pods fit all sizes of the Pet Loo. One pack includes 7 pods plus the Wee Sponge powder and scoop and lasts about 21-28 days, depending on how often your pet uses the Pet Loo.