Trouble-free Biological Filter designed with adjustable 1 uplift tubes for better water circulation. Multiple plate construction for easy installation. Includes airline tubing and Discard-A-Stone and has a fish’saver feature. Advance design allows separate plate installation and features optional flow-thru set-up which can be used with a power head. Made of special quality plastic which resists splitting and cracking. 7-1/2 x 15