Package content: there is 1 piece of trimmer head and 12 pieces of trimmer head replacement blades in this package, a nice combination set for you, saving your time of purchasing blades again Compatible with Stihl 20-3: this trimmer head and replacement blade set is compatible with ST20-3, which doesn't fit for other models; The blade is 11 cm in length and 3.5 cm in thickness, the trimmer head is 13.5 cm in diameter, and 5 cm in thichness, the size of the spiral is 10 x 1.25 cm, please check your machine model and check the size before purchasing to make sure it's the right fittings for you Make garden more beautiful: just replace the old or broken trimmer head and blade of your lawn mower, and use new tool to improve your weeding efficiency, so as to create a more beautiful garden Quality material: made of quality plastic, these trimmer head is strong enough and not easy to break; The replacement blade tool is made of nylon, durable and study to use, not easy to wear, both materials can be applied for a long time Easy to replace: 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 Trimmer head with 12 pieces trimmer head replacement blades compatible with Stihl Polycut 20-3 for patio, lawn, garden Features: Work more efficiently: Just replace the old or broken trimmer head and blade of your lawn mower, and use new tool to improve your weeding efficiency, so as to create a more beautiful garden. Please note: This trimmer head and replacement blade set is compatible with Stihl 20-3, which doesn't fit for other models, please do check your machine model before purchasing to make sure it's the right fittings for you. Specifications: Color: as shown in the picture Trimmer head material: plastic Blade material: nylon Trimmer head size: Diameter: 5.3 inches/ 13.5 cm Thickness: 1.9 inches/ 5 cm Blade size: Length: approx. 3.9 inches/ 10 cm Hole diameter: 0.5 inches/ 1.2 cm Package includes: 1 x Trimmer head 12 x Trimmer head blades