The AquaC Remora and Remora Pro are undoubtedly the most efficient hang on skimmers available today, and what better than an accessory that boosts their performance by as much as 20%! The AquaC Surface Prefilter is a special box designed to hide the skimmer pump, thereby creating a more aesthetically pleasing aquarium. The Surface Prefilter isn`t just about looks, however. Ever notice that oily "skin" on the top of your aquarium? The Surface Prefilter skims water off the top of the tank, which is often coated with a heavy load of organics. This can improve skimming by as much as 20% (much darker, smellier foam), and the prefilter has a slotted edge just like an expensive overflow box. The Surface Prefilter also contains a bubble eliminating sponge to get rid of those microbubbles that sometimes escape back to the aquarium. The water return area can also serve as a media chamber for those who choose to use activated carbon or phosphate removing compounds. The Surface Prefilter installs in seconds and requires no tools - just attach to the pump and turn your Remora or Remora Pro hang on skimmer into a waste removing machine! Dimensions (L x W x H): 10.34" x 8" x 4.25"