I made one for my wife, who is height challenged (AKA short). Out of 3/4 plywood, I cut a small round circle, drilled it 4 times at equal intervals around the circle, and glued in 4 short 1/4 inch dowels to fit around the roof vent knob. Cut a length of 1/2 inch dowel (24 inches) and put a screw through the center of the circle into the 3/4 dowel. Last, drilled a cross hole in the other end of the 3/4 dowel and glued in a 4 inch length of dowel for a handle. Works great, DW loves it, and it cost less than $1 and 30 minutes of time.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.