The tune up kit fixes problems with air output and/or increased noise. Includes the diaphragm and valve block for the 300 / 400. These parts are the most likely to wear out during normal use. From our experience the life expectancy of these parts is about two years but can range from as little as one year to as much as five years depending on operating conditions. The Rena Air 400 will require two complete kits to repair both sides.
