The Reef Octopus Classic 150-SSS Protein Skimmer packs 210-gallon skimming capacity into a Space Saver Sump body that fits narrower compartments than the standard 150-INT footprint. It's the go-to choice when a sump's baffle spacing was designed for a smaller skimmer than the tank's bioload actually needs. Best for: reef and mixed saltwater systems up to approximately 210 gallons with limited sump width Setup: in-sump, space-saver cone footprint Pump: needle-wheel pump for fine, stable microbubbles Maintenance: adjustable gate valve for wet/dry skimmate Measure your sump compartment before ordering — the SSS body is narrower front-to-back than the standard 150-INT, which is exactly what makes it fit where the INT can't.Compatible replacement parts: Classic 150 series pumps and collection cups.