Multi- application trimmer head with bump knob. Fits 95% of commercial straight shaft trimmers. Holds up to twice as much as most other heads. Designed and built for commercial use. Manufactured with special high quality long lasting nylon. Bumper contains added glass fill to promote even longer life. Available with of with our hardware. Hardware contents include the following mounting bolts: 8mm x 1.25 Female Left Hand, 8mm x 1.25 Male Left Hand, 10mm x 1.25 Female Left Hand, 10mm x 1.25 Male Left Hand, 10mm x 1.0 Female Left Hand., 7mm x 1.0 Male Left Hand.