Introducing the newest additions to the Polaris 3900 sport PosiDrive System- Polaris 3900 is an all wheel driven cleaner. The stainless steel drive chain provides the most reliable and efficient drive transfer available. Polaris 3900 is an all wheel driven cleaner. Features Include:*Wide Trax Tires - Wide Trax tires provide superior torque transfer resulting in aggressive wall climbing. *Improved torque - 50% more torque drives cleaner out of tight difficult areas.*Optimized Vacuum Power With the most vacuum power of any 3-jet Polaris cleaner. The 3900 Sport venturi vacuum system creates 40 GPM of additional pool filtration through the filter bag. This results in a clearer body of water. *Twist Release Bag Design New twist-release bag connection and fully zippered access to pockets makes cleaning simple and improves durability. A 5-liter capacity bag means less cleaning required. *Sporty & Sleek body design sets a new standard in the Automatic Pool Cleaner category.Visit www.polarispool.com for more info