QMP520 is a 1/4” Compression Diverter Valve Return that connects to your kitchen faucet.
This diverter valve allows you to switch between the tap water from your faucet and filtered water from the unit. The tubing attaches snuggly to the compression connection and diverts the water to the filtration unit when you pull the pin out.
Simply push the pin back in to return to regular tap water. The unique return feature on this diverter prevents the filtered water from getting mixed with tap water.