The Octo Skimmer Neck Cleaner has been designed to keep the collect cups neck free of bio-organic build up. By doing this you ensure your protein skimmer is running at its best. The blades periodically wipe the inside of the neck and remove any build up. The bio-organic matter which causes foam to stick to the sides restricts the collection of skim matewithin the cup and reduces its effectiveness, the neck cleaner ensures your skimmer is running at its best. To operate this easy to use skimmerdevice, you simply plug the unit into a timer (not included) or aquarium controller and set it to run for a few minutes 4 to 6 times per day. By running it this way it prevents build up along the walls of you skimmers neck. This will greatly reduce the need to stop the skimmer for manual cleaning. Note: Requires controller or timer to operate. Features Twin Blades Prevents the Buildup Within the Skimmer Neck Automatic* Solid Construction Sealed Accessible Drive Motor * Requires a controller or timer Octopus Cleaner 250fits: SRO5000(int/ext/sss), NWB/DNWB250, XP5000(int/ext/sss), XS250, EXT250 , EXT300, EXT350, DCS 250, DCSR 250ext, Regal 250(int, sss, ext), Hurricone Cat 2(int/ext)