All kinds of precision motor housing, back cover series: K, M, N, 030, 050, 130, 131, 132, 140, 180, 260, 280, 300, 310, 320, 370, 3 series, 5 series, 7 series, all kinds of brushless and 16, 18, 20 electric sonic toothbrush motor series housing, back cov