The Little Giant "Q" Series Aquarium Pumps features a wide range of magnetic drive pumps specifically designed for saltwater and freshwater aquarium applications. The motors are thermally protected and the pumps are UL listed and CSA certified for aquarium applications. All these Little Giant pumps have 6' cords. The MDQ Little Giant pumps are for use in pressure situations ( in-line pressure canister filters, protein skimmers) The MDQX Little Giant pumps are for use in free flowing set-ups (direct tank return applications, wet/dry filters)