The mark consists of a circle featuring the letters "H" and "D" interwoven inside. The circle stroke varies in thickness, composed of a thinner stoke along its vertical edges, and gradually expanding to double the thickness along the horizontal edges. The "H" is composed of two vertical strokes of even thickness, with one vertical stroke running through the middle of the circle, and the other slightly off-center to the left, with each extending to the top and bottom boundaries of the circle. The "D" is represented as a smooth, curved stoke branching off of the inner-bottom right side of the circle, closely following the circle's inner contour before the top of the "D" thins into a horizontal line crossing the two vertical lines forming the "H" at a point slightly higher than the center of the circle.