Are you looking to set up a custom bio-active terrarium with a DIY background? Aquascape Waterfall foam is designed to be used in an aquarium setting; you no longer have to do the guess work standing around inside a hardware store wondering if the expanding foam they have is 100% safe for reptile use! This foam has the added value of being black instead of white. Making a headache-less build trying to cover all the white foam with substrates and cork. Water-resistant expanding foam sealant Seals gaps/spaces between boulders and rocks Maximizes the flow of water over waterfall features Easy to use – includes extension tube applicator Safe for use around pond fish NOTE: This size expandable waterfall foam has been designed for with the use with a foam gun applicator. If you want foam that does not require an applicator gun then check here.