Feature 1It can be used for protein separation to increase dissolved oxygen in water. 2Made of high quality acrylic material, clear view and strong structure, durable in use. 3Practical fish tank accessory, it is designed for 20-30cm fish tank, reliable to use. 4This protein skimmer is mainly used to filter marine water quality, not for fresh water. 5It can separate the organic matter before it decomposes into toxic waste, reducing the burden on the biochemical system.Condition: 100% Brand NewItem Type: Protein SkimmerMaterial: AcrylicTotal Length: Approx. 26.5cm / 10.4inWeight: Approx. 184g / 6.5ozUsage:1. Partially submerged, partially exposed surface.2. Not for fresh water.3. It must be driven by an air pump. .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; }Package List1 x Protein SkimmerNote1. Please allow 0-2 cm error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.