Silent-Air X4 Air Pump, 2-Outlet - Up to 65 Gallons DESIGNED FOR DURABILITY AND RELIABLITY: the Penn Plax Silent Air Pump 4X is virtually silent and still operates at high performance FEATURES OF THE SILENT AIR PUMP: the Silent Air Pump features a unique diaphragm mount armature, quiet design casing, non-skid feet, and silicone polymer flappers. MULTIPLE SIZES AVAILABLE: this air pump is for tanks up to 55 gallons in size, but Silent-Air pumps come in multiple sizes for aquariums from 10 to 75 gallons. SHOP PENN PLAX FOR ALL YOUR AQUARIUM NEEDS: Penn Plax sells items including stunning tanks, breeding tanks, ornaments, and dcor, as well as air pumps, vacation feeders, bubble walls, nets, dividers, thermometers, gravel vacuums, algae scrapers, air tubing, toxin removers, air stones, filters, cartridges and more.