Makita is giving landscapers more options with both MM4 4-stroke engine and the 13 in. string trimmer couple shaft attachment is the right accessory for use with this versatile system. It quickly attaches to the power head for easy operation. The M10 x 1.25 LH shaft arbor fits common sized trimmer heads for increased versatility, with bump and feed for increased efficiency. The steel drive shaft is engineered for lower vibration and longer service life.