Hayward AquaNaut 400 Suction Side Cleaner | W3PHS41CST Style_Vantage The rear cover kit is

The rear cover kit is a replacement part made by Pentair

could be due to the scrubber or strip clip being worn

Less noise

Note: This is only the replacement UV Bulb

Hayward AquaNaut 400 Suction Side Cleaner | W3PHS41CST Style_Vantage The rear cover kit isHayward AquaNaut 400 Suction Side Cleaner W3PHS41CST The AquaNaut 400 automatic suction pool cleaner was amongst the first clog eliminating and all terrain suction cleaners on the market and remains the best in the class. AquaNaut is designed with patented technologies that deliver superior traction, power, and balance for pools of all shapes and sizes debris types, and flow rates. The self adjusting variable vanes known as V Flex technology,