API float shoe 1. Size:from 4 1/2" to 20" 2. Thread:BTC,LTC,STC 3. Grade:k55,J55,N80,P110 4. Single or double valve API float shoe 1. DescribtionThe float shoe which is connected at the end of casing string functions as guide or back pressure valve. It is a kind of casing shoe which can produce buoyancy. With the advantages of high temperture resistance, good sealing feaure and easy connection, ...