PREFILTER BOX KIT 9" 9" x 4" x 6" Prefilter Box (Maximum recommended flow rate 500gph) # 6" x 2.75" x 6" Adjustable height Skimmer Box w/ Easy click leveling device Top and bottom feed skimming for simple and more accurate flow control Deluxe Swivel Duckbill Return Elbow assembly to accept , 5/8 or  flexible tubing FREE SHIPPING within continental US