Perfect for use as a Biological, CO2, Carbon, Calcium, Nitrate, or Phosphate reactor. May be used with granulated substrate or foam based pads. Comes complete with: 12? high x 3" diameter hanging Reactor (Maximum recommended flow rate 50gph) Secure, easy fastening Lid Lid mounted complete Intake Elbow assembly with dual 5/8? and ¾? barb Lid mounted deluxe swivel duckbill Return Elbow assembly Sturdy Hanging bracket Bottom mounted multi-positional Leveling Device Two plastic diffusion Retainer Screens Two reticulated 3? x ½? Foam Retainer Discs The Reactors are made of all hi-impact clear acrylic with color ABS brackets and screens and polypropylene fittings. Reactors come individually packaged in white corrugated boxes with a UPC sticker on the box.