A round mandrel slip joint compensates for the movement associated with ocean heave or temperature change without allowing the movement to disturb the placement of downhole dst tools. A slip joint operates by balancing its volume through the slip joint stretches and increases its internal volume,. Each slip joint has 5 ft of travel but can be combined with other slip joints to provide additional travel. Slip joints are designed to transmit the torque or rotation required to operate tools such as packers or safety joints.