* does not include the 4 screws, so plan on re-using your old ones.
*** Kit is to fix the problem of a unit that never shuts off ( OR never turns "on" to make water ).
The ASO is the Automatic Shut Off control for the Microline R.O. system.
If the diagraph fails to seal, the unit will continue to run water.
If the diagraph fails to "open" the unit will not product water
( ASO things your Tank is FULL .... also TOO MUCH Air Pressure in the Tank will cause same problem ).
Only other possible reason, would be if the Drain Line Restrictor was missing, or no longer "restricting" the flow to drain
( resulting in the membrane producing little to no water to fill the holding tank ).
For more about HOLDING TANK issues ( and proper air pressure ),