Red Sea Fish Pharm ARE50181 Deluxe Prizm Hang-On Skimmer with Pump for Aquarium The surface skimmer attachment allows for the top surface water to be drawn into the water inlet pipe of the skimmer A surface skimmer attachment is included which is an important incorporation because roughly 70-percent of accumulated protein The second upgrade is the inclusion of a refillable media basket This basket can be filled with either biological or chemical media to obtain the desired results Measures 2-2/5-inch width