Great for nano tanks, use with the principle of differential pressure to automatically refill water, simple and practical. You need to prepare 0.5-1.5L (16.9-50.7 FL Oz) plastic water bottles such as EVAIN / Coca Cola / Fiji yourself.Built-in noise reduction device can effectively reduce noise. (Note: not completely silent). Screw-free, no damage to the tanks. Made of corrosion-resistant ABS material, which is also usable in saltwater. The length of the tubing (manually cut) allows you to adjust the water level. Suitable for tanks with 3-10mm /0.12-0.39in wall thickness. Note: Incompatible with rimmed tanks and curved fish tanks; and tanks with 3mm/0.12in or 5mm/0.2in thickness wall need to use the self-adhesive gasket (included). A reliable gadget during business trips or travel. Compatible with fish tank, tortoise tank, planted aquarium, saltwater aquarium, etc. For tanks longer than 40cm/16inch, it is recommended to use 2 refillers together.