This grommet is an OEM part that is a 45-degree elbow for the crankcase breather tube of your mower engine. That is why it is also known as a 45-degree breather tube. The part is made of rubber and is black in color. You must purchase this part individually. Your grommet may require replacing if you notice dark smoke coming out of the exhaust. This is a telltale sign that your grommet has become cracked and damaged. Other symptoms are a reduction in the mower performance, or a backfiring engine. According to our customers, this is an easy repair. It requires no tools. Simply attach the grommet to the breather tube from the crankcase to the carburetor.