The Type D Collar Lock Mandrel is used to land and lock in an API tubing collar torqued to specification, design to seal at the set position and retain a pressure differential from above or below within well bore. The lock element is mechanically locked in the collars internal cavity as the element is then expanded creating an isolation barrier. The WPC D lock can be used in conjunction with pump thru valves, standing valves or choke assemblies as desired. The standard D lock configuration is equipped with a knockout kobe to equalize pressure differentials previous to pulling. Specifications: Available upon request.