Description:Package Content: You will receive 2 piece black aquarium filter sponges fit for XY-2822/2821 practical replacement accessories.Main Function: Biochemical sponge filter provides biological filtration to the aquarium helps increase biological capacity increase the oxygen solubility helps keep the fish tank clean.10-Layer Ribbing Shape Design: Quickly established a bio-filter and extra oxygen provides more surface area for beneficial biological colonization and faster cycling.Durable Material: This aquarium water filter sponge is made from sponge material soft and safe for aquatic pets good permeability durable washable and reusable.Replacement Part: Clean the sponge approximately every 2 weeks it is recommended to replace the filter sponge every 5 to 6 months at most giving your fish a healthy and clean living environment.Specification:Material: SpongeColor: BlackSize(DxH): About 6x12cm/2.36x4.72inchPackage includes:2pcs x Aquarium Filter SpongeNote:1. Due to the light and screen difference the item& 039;s color may be slightly different from the pictures.2. Please allow 1-2 cm differences due to manual measurement.