This was created to solve the problem of the lever arm being too small and never knowing which way to turn the valve off.
The OFF nomenclature is on both sides. Arrow is cut through. If your valve closes the other way for some odd reason, flip the lever over. Hole is to drill and pin with a roll pin to secure, if needed. This does press onto the existing handle which has a slightly rubbery feel. The valve was purchased at Home Depot. Manufacturer is Orbit and the part number is 442-559.
Designed in Fusion 360, f3d file included for rework.