Central region of K04166 obtained from the 1 mm-high data with Briggs weighting. The background grayscale represents the polarization fraction, and the magenta contour represents the total intensity at [10, 20, 50, 200, 600, 1200, 2000]×25 µJy beam⁻¹ levels. The orange segments correspond to the polarization vectors within the area where the fraction is lower than 3%, whereas the green segments correspond to the 90◦ flipped polarization vectors, B-vectors, within the area where the fraction is larger than 3%. The orange-shaded ellipse corresponds to the convolved size obtained with 2D Gaussian fitting. The contour at 200×25 µJy beam⁻¹ levels is comparable to the transition area of 3%, which has the projected size of ∼0.51″×0.36 ″(80 au×56 au). The blue and red arrows are the outflow direction, and the gray ellipse corresponds to the beam.