The Polaris 180 is a great little cleaner, and unlike its brothers, incorporates a different drive system. It is a three-wheeled vehicle that sweeps and scrubs the bottom and walls of your pool. This is the original design by Polaris and has served for many years as a good cleaner for those pools that catch leaves and other things such as acorns. Being a lower priced unit, it also has less moving parts then its bigger brothers. For the lesser expensive cleaner for dirty pools, the Polaris 180 is an excellent choice.