The grades 8.8, 10.9, and 12.9 refer to the strength or hardness of the plow bolt and nut, also known as a plough bolt. These grades classify the bolts based on their tensile strength and ability to withstand loads.A plow bolt is typically used in construction and agriculture equipment, such as plows, graders, and bulldozers. It is designed to securely fasten various components of the equipment together.The grade 8.8 plow bolt and nut have a tensile strength of 800 MPa and are commonly used in general applications. The grade 10.9 plow bolt and nut have a tensile strength of 1000 MPa and are suitable for heavy-duty applications. The grade 12.9 plow bolt and nut have a tensile strength of 1200 MPa and are used in critical or high-stress applications.When choosing plow bolts and nuts, it is essential to consider the recommended grade based on the equipment and load requirements. Using the appropriate grade ensures the strength and durability of the fasteners for their intended purpose.If you need specific plow bolts and nuts or have further questions regarding their specifications or availability, please provide more details, and we will be happy to assist you.