Keson RRT12 3' Circumference Top Reading Center Line Measuring WheelKeson RRT12 3' Circumference Top Reading Center Line Measuring Wheel The RRT Series focuses on control and comfort. Resetting has never been easier with two options, a reset on the handle AND on the unit housing. The center line handle design makes this unit well balanced. Our compact folddown uses a collapsing hinge and handle lock to reduce the unit to half its original size. Features: Enhanced grip pistol type handle increases control and comfort.