Designed to replace Harken rudder bearings. Many J-boat, including the J-120 are due for major rudder bearing service or replacement. These bearing fit without modification to the boat. J-120 Upper Bearing- Self aligning roller bearing with a mounting flange. The ball is easily removable with tools for cleaning and service if needed. The bearing is shipped with a stainless steel sleeve to bond to the rudderpost. This sleeve has holes for the upper and lower pins used in the original bearings. Flange OD=8", Body OD=6", Height 2.83", Sleeve height= 8"