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This part has been discontinued by the manufacturer and is no longer available.
This is a replacement bump knob for a gasoline-powered string trimmer used for cutting light weeds and edging lawns and driveways. The bump knob is a hard plastic attachment that is snapped onto the end of the cutting head assembly of the trimmer. Also known as a bump feed knob, this part releases about one inch of line or string from a spool inside the cutting head assembly each time the operator taps it on the ground or pavement. This enables the operator to keep operating the trimmer without stopping to advance a worn or frayed string manually. Pushing down on the bump head also releases the end of the trimming line so a new spool of line can be installed. The bump knob is simple to install, by snapping it onto the bottom of the gearbox shaft. It may need replacing due to normal wear and tear or after cracking or scraping on hard surfaces. This part fits several models of Craftsman and MTD string trimmers, also known as weed whackers. This is a genuine OEM part sourced directly from the manufacturer and is sold individually.