The Aquarium Gravel Cleaner was developed to make routine water changes and vacuuming gravel easy and efficient. Auto-start valve makes water siphoning easier than ever. Simply shake the vacuum up and down a few times while submerged in your aquarium and the water will begin flowing automatically. Perfect for quick water changes Self-priming, using up and down motion, to start water flow Efficiently separates debris from gravel Easy to use this pump,Ideal for water changing and gravel cleaning. A long time use Aquarium water changer handy tool,you can clean the aquarium easily. Material: plastic.