The Python Pro-Clean Gravel Washer & Siphon Kit is perfect for the beginner and experienced hobbyist alike. It effectively separates and removes debris from your aquarium while you perform routine water changes. This special kit also includes the Python Squeeze Siphon Starter. This handy accessory eliminates the need to start a siphon with your mouth. The Python Pro-Clean and Squeeze accessory are both constructed using only the highest quality materials. The Medium size is ideal for aquariums up to 20 gallons in size.