1.Qualified Material: manual Aquarium Dropper is made of premium non-toxic plastic material for durable and practical use. It will not harm your fish. You can use it rest assure. 2.Easy to Use: the amount of water absorbed by dropper can be adjusted by controlling the strength of grasping the dropper end. Please clean the item before use. 3.Scale Design: the small Aquarium Dropper pipe has 4 scales (10ml/15ml/20ml/30ml), the large dropper has 5 scales (10ml/20ml/30ml/40ml/50ml), and the pipe has clear printed scales. This aquarium water transfer tool features clear and precise markings so you can easily measure liquids. 4.Keep Fish Tank Clean: The Aquarium Dropper can remove the dirt and residual feed at the bottom of fish tank. Perfect for stirring up waste and sucking it up without stressing the fish out too much. Help to keep your fish tank clean. Product details: size: 30ml: 11inch, 37g 50ml: 18inch, 55g Color: blue + white Material: Acrylic + plastic