This Bundle has THREE items: the Reef Octopus OCTO Regal 150SSS Protein Skimmer; a FREE MarineAndReef Reefractometer; & a Towel. For aquariums up to: 210 gallons, light bio load; 160 gallons, medium bio-load; and 100 gallons, heavy bio load. This Regal skimmer is equipped with a new generation Reef Octopus controllable Direct Current VarioS 2S pinwheel skimmer pump, the latest variable speed flow technology, allowing for refined control, enhanced performance, and efficiency. Most skimmer pumps available to hobbyists are alternating current "AC" pumps (the type of power that comes out of your wall outlet). VarioS-2S Pump Features: Safe and Efficient 24V Power; 0-10v Input for 3rd Party Controller; Integrated Memory; Two pause/feed modes will shut off the pump at 15 or 60-minute intervals; 5 Controllable Energy Saving Power Settings; Detachable Controller with Waterproof Union; and a Safety Float Switch. Technical Specs: Body: 6"; Footprint: 9" x 7.5"; Neck Size: 5.5"; Total Height: 23"; and Output Size: 40mm/1.25". Recommended Sump Water Height: 7 - 8.5". The SSS in the name stands for Saves Sump Space. This In-Sump only Skimmer has a small footprint for a Skimmer that is so powerful. The MarineAndReef Reefractometer is designed specifically for marine and aquarium salt water. The readout is for 0-40 PPT, which is much easier to read than the 1-100 PPT that comes with many refractometers that are for general use. The MarineAndReef Aquarium Cleaning Towel is a durable, lint-free microfiber towel. 19" X 15". This Bundle has THREE items: the Reef Octopus OCTO Regal 150SSS Protein Skimmer; a FREE MarineAndReef Reefractometer; & a Towel. For aquariums up to: 210 gallons, light bio load; 160 gallons, medium bio-load; and 100 gallons, heavy bio load.