The float shoe or float collar is a kind of casing shoe or coupling which can produce buoyancy. With advantages of high temperature resistance, good sealing feature and east connection, they can be used to replace guide shoe or casing shoe. The float shoe and float collar can be not only used in unclassified technical casing, oil layer casing but also in deep well, extra-deep well and special technology well.

The float shoe which is connected at end of casing string functions as guide or back pressure valve. The float collar which is connected at 20~30meters from the end of casing serves the functions of supporting ring and back pressure valve.