EM403MP 17′′ String Trimmer Couple Shaft Attachment Makita is giving landscapers more options with both MM4 4-Stroke Engine and 36V (18V X2) LXT couple-shaft power heads (sold separately), and the Brush Cutter Couple Shaft Attachment is the right accessory for use with this ...EM403MP 17′′ String Trimmer Couple Shaft Attachment Makita is giving landscapers more options with both MM4 4-Stroke Engine and 36V (18V X2) LXT couple-shaft power heads (sold separately), and the Brush Cutter Couple Shaft Attachment is the right accessory for use with this versatile system. It has a 10 mm left-handed thread shaft arbor that fits common sized trimmer heads for increased versatility, with a large multi-purpose grass shield that can be used with a trimmer head for grass blade. It has a bump and feed trimmer head for increased efficiency, with a steel drive shaft that is engineered for lower vibration and longer service life.