Submersible pumps designed specifically for hydroponic systems. Powerful mag drive construction Indoor use Oil free and environmentally safe BPA free—safe for aquaponic use One year warranty 6' power cord Has 5/16" fitting for 5/16" ID tubing. 1/4" ID tubing will fit inside fitting. NOTE: Models 40 GPH-160 GPH contain a steel shaft and are not suitable for saltwater applications. Larger pumps (250 GPH-1000 GPH) have a ceramic shaft, and these are suitable for saltwater operation.