4151s is the Rocker Swivel Recliner Mechanism . It fits the same frame as Glider and Swivel glider . More comfortable with optional spring and wood accessories in rocking system. Available with Cable/Lever, outside handle and inside handle. Application for Chair, Lover seats, Sofas ,Sectional and home theaters. Geometry theory used to allow occupant’s weight to balance chair operation. The 4151s has only one stop position in the rear of mechanism which allows a greater range of motion. while 4153 has two stops with less range of motion. the other functions are same. All Recliners are interchangeable in the same frame if the frame is constructed for Rocker and Two-motor lift.