The length of the extension tube matches the length of the tube that fits in between the intake strainer and mid-level strainer (sold separately) of your Bio-Wheel Filter.
Extension Tube for the Penguin 100B/150B/200B Power Filters. The length of the extension tube matches the length of the tube that fits in between the intake strainer and mid-level strainer of your Bio-Wheel Filter. Great device to use to help evenly filter aquarium water for really tall tanks. A mid-level strainer (sold separately) is required to connect to the intake tube.