We added our T-Bar power Knob to Original Avet Power handle Arm. The length of handle is 4.25" (108mm) This is for current Model Single Speed SX, MJX, MXL, JX, LX, MJX, HX, HXW Reels. Quote from Avet web site. The handles on all current model Avet casting reels are interchangeable between all single speed models SX thru HXW, and also interchangeable between all 2-speed models SX thru HXW. They are NOT interchangeable between single and 2-speed models, as the drive shaft hole size is different. To order a "power handle" (longer length / more leverage) simply order the handle length for a larger reel model. The table below indicates the handle lengths that come by default on Avet Reels. Specify single or 2-speed, and color when ordering.