All the three of them operate on the basis of TUNZE "Flash Skimming Principle“, which performs a rapid protein extraction from the aquarium water without long internal dwell time. Comline DOC Skimmers 9004 und 9012 use a combination of water inlet for the protein-loaded aquarium surface and a fine air-bubble generation with a needle wheel. Both of these factors combined deliver an extremely high skimming capacity, whereas such a high-performance device would have been at least four times as big 20 years ago. The internal TUNZE Foamer is a new type of skimmer pump, that generates a large amount of fine air bubbles with very low power consumption, and without an impeller housing or hydraulic losses. The foamer operates very quietly. Due to the advances in technology and the resulting miniaturization capabilities, the device could be reshaped to provide a maximum degree of skimming capacity on a very small footprint, with highly appealing and clean design lines. In a time where even the aquatics market is being flooded with unnecessary accessories, the Comline DOC skimmers represent an intelligent solution which can greatly simplify this wonderful hobby. The Comline DOC skimmers are also highly suitable as a „Stand-Alone Solution“ within the aquarium, without the need for an external system and the associated risk of water damages. The devices are delivered installation-ready with a Magnet Holder.