Kelly 1.Certificates:API,ISO,etc 2.Working pressure 10000PSI~15000PSI 3.Size from 2 1/2" to 5 1/4" 4.MOQ: 1 Roll Kelly 1.Certificates:API,ISO,etc 2.Working pressure 10000PSI~15000PSI3.Size from 2 1/2" to 5 1/4"4.MOQ: 1 Roll We are "Petrochina" Subcompany !Kellies are the driving section of whole drill stem. Kellies are available with square kelly and hexagonal Kelly. TIANHE brand Kellies are ...