Suitable for marine and tropical aquariums. Easy to use, for external use. ETH Heaters are the first external heaters for aquariums with exclusive PTC technology, designed to be used on return lines coming from canister filters or sumps. This item is in the category "Pet Supplies\Fish & Aquarium\Heaters & Chillers". The seller is "coloris_54" and is located in this country: TW.This item can be shipped to United Kingdom.