This is a designed to hold the rear flap on the lawnmower open.

When cutting very long grass (first cut of the year) the mower gets clogged up, using this allows the grass to be blown out of the back a lot more efficiently.

Note: As anything that is being sucked up and blown out by the mower is being blown directly toward the operator, you must ensure you are wearing adequate protection (especially eyes) against any debris. If in any doubt as to your safety using this mod then please do not use