Do I need a lever clip to use a Fumoto valve? 

Lever clips aren't a necessary component to install and use a Fumoto valve. However, they are great to add extra security to the valve lever.

By using the lever clip (which is now included with all F-type valves), you're reinforcing the valve lever, as the clip fastens to the head of the valve to protect the lever from moving in the event that debris hits in on the road and it is also a great reminder to close the valve all the way since you cannot install the LC-10 Lever Clip unless the valve lever is in the closed position.