The float collar and float shoe are mainly used to guide the casing string into the well smoothly, adjust the buoyancy force on the casing string when running the casing, prevent the cement slurry from flowing into the casing through the back pressure valve, and accurately control the height of the cement plug in the casing during cementing, thereby ensuring the quality of cementing. Float hoop and float shoe are generally used in a complete set. The float shoe is at the bottom of the casing, with 1-2 sleeves separated between the float hoop and float shoe. The float hoop can be used for rubber plug pressure.