1. Our grass trimmer accessories originally came with three high quality thick nylon blades, which are wear-resistant and durable.Since blades are consumables, we also provide you with 20 replacement blades.It is convenient for you to use. 2. Our lawn mower accessories have a diameter of 9.4cm and a thickness of 5cm.The length of the replacement knife is 10.5 cm.The diameter of the mounting hole is 1.2cm and the thickness is 0.4cm.Our nylon replacement blades are attached to the lawn mower accessories with screws and are not easy to fall off during use.They can also improve work efficiency and provide you with great convenience. 3. Our replacement blades have a smooth surface and excellent craftsmanship.Be careful when holding the blade to prevent the edge of the blade from scratching your hands.(Note: The blade is a small accessory. Please place it out of the reach of children to avoid eating and scratching.) 4. This nylon trimmer blade can be compatible with stihl ST 20-3 and is easy to replace.Simply remove the lawnmower screwdriver and replace it with a new blade. 1. The blade is a small accessory.Please place them out of the reach of children to avoid eating and scratching.