MR400, MR4000, MR4050, MR5000, MR5500, MR6000, MR6500. TYPE NUMBERS: 4179, 4191, 4192, 4193, 4194. GENUINE BRAUN COUPLING. THIS DRIVE COUPLING CAN BREAK IF TOO MUCH LOAD HAS BEEN APPLIED AND IS A VERY CHEAP FIX COMPARED TO PURCHASING A COMPLETE BLENDER SHAFT!