This kit is to install a valve to control the flow from the Purge Trough on the Dr. Oligo to the waste box. The original design has a small ID tube as a drain tube. The small ID tube limits the gas leak rate to waste however it also tends to get plugged. Adding this upgrade changes the tube to a large ID tube and adds a solenoid valve to control the flow. With this kit flow only occurs during a High Drain step.