Perfect for both aquarium and terrarium use, the Hydor Hydrokable is a flexible heating cable designed to distribute regular and even heat from beneath the substrate. It creates a slow water circulation effect throughout the media, which is beneficial to live aquatic plants and other tank inhabitants. This double insulated, fully submersible system operates safely in or out of water and includes the required suction cup mounts for easy and secure installation. The safe and reliable 25 watt Hydrokable is suitable for use in aquariums 10 - 18 gallons in size. Ideal for freshwater and saltwater applications.