Replacement Part Number:4002 710 2189 ； for Stihl Polycut 20-3 Trimmer Head Compatible with: this trimmer head and replacement blade set is compatible with Stihl 20-3, which doesn't fit for other models; The size of the spiral is M10 x 1.0 MM in length and width, please do check your machine model and check the spiral size before Fitment:for STIHL FS44 FS55 FS56 FS70 FS80 FS83 FS85 FS90 100RX FS110 FS120 FS130 FS200 FS250 KM55 KM56 KM 85 KM90 KM110 KM130 + FS-KM Packang include 1 piece of trimmer head and 6 pieces of trimmer head replacement blades， it's easy to replace the trimmer head blade, just remove the screwdriver of the lawn mower and replace it with a new blade, saving your time and effort in daily life We firmly believe that communication is a good way to solve problems. If you are not satisfied with this kit in any way, please feel free to contact us 4002 710 2189 Trimmer Head (M10*1.0 left ) for Stihl FS44 FS55 FS56 FS70 FS80 FS83 FS85 FS90 100RX FS110 FS120 FS130 FS200 FS250 Trimmers Replace for Stihl Polycut 20-3 Trimmer Head