Sporty’s now offers a Seat Height Sight Level, similar to devices found on business jets and airliners, to make sure your seat is at the correct height while flying.
Pilots place the Seat Height Sight Level on the dash before engine start. It features a bubble level to ensure it’s giving an accurate indication, and a bright orange sighting sphere is highly visible even in low light conditions. When the two balls are lined up, the seat is at the right height and the Sight Level can be removed.
Constructed in the United States of aircraft-grade billet aluminum, the Seat Height Sight Level works in any type of airplane, and requires no installation.
Measuring 5.5 inches high, the Seat Height Sight Level [7346A] is available for $89.95 at Sportys.com or by calling 800-SPORTYS.

$90.00 for a useless tool?
This is what is wrong with general aviation.
Is there ANYTHING they wont try to sell you?
How did I fly for all these decades without one of these?