A.長約50mm,錐度為1:20,大端比管孔大0.025~0.05mm B.長約40mm,錐度為1:25,大端比管孔大0.025~0.05mm C.長約40mm,錐度為1:20,大端比管孔大0.025~0.05mm D.長約50mm,錐度為1:25,大端比管孔大0.025~0.05mm