FUNCTION --- Easy to control, convenient to siphon fish faeces, impurities, turbid water out of fish tank. 7 Feet HOSE --- Made from clear & elastic plastic. Makes it more durable and anti-kinking. Harmless to fishes & No peculiar smell. GRAVEL TUBE --- Sinkable, with a filter screen inside. Will not disturb fish or decor when it's working. SIPHON BALL --- All you need to do is to pinch it several times, water will flow out automatically. Without striking a blowing. WARRANTY --- For 3 months after the date of purchase, we take care of all quality-related issues with a FREE replacement or refund. If you have any questions, do not hesitate to contact our professional after-sale service.