Choosing a Classic external filter is a decision you can't go wrong with. You are opting for a reliable device that has been proven millions of times. All models meet the highest quality standards. Top-notch components and carefully coordinated functions ensure perfect pumping and filtering performance. Additionally, there is the legendary Eheim quiet operation, robust durability, and low power consumption. You will be very satisfied. There are 5 models available for aquariums ranging from 50 to 1500 liters, some with different features.