This kit is needed only if you plan to change one of the NR Gas valves on your Dr. Oligo to the new Pneumatic Gas Valve. To make this change you will need this kit plus you will need the individual pneumatic valve assembly for the particular gas valve you plan to change. Once you have changed one of your Gas valves to the new Pneumatic valve, if you need to change another NR Gas valve to a Pneumatic valve you do not need this kit again. An alternative way to go is to change all 5 NR Gas valves to pneumatic valves at the same time. There is a different upgrade kit available that changes all 5 of the NR Gas valves to pneumatic valves. The Part Number for the complete kit is: 351-105012. The complete kit has all the items needed to change all 5 Gas NR valves to pneumatic valves.