Current part number 193406 replaces previous part numbers 184219, 532193406 and 539107608. Replacement part for many brands including Husqvarna, Poulan, Poulan Pro, Roper, Sears/Craftsman, John Deere, more. Use for wheels with 2/1/2" Deep Hub. Locknut is not FSP, however, is a high quality Grade 8 locknut.