The calculation =( of 2 under the root)×L/200 is engraved on the micrometer net, where L represents the length of the bottom side of the rectangular grid. n represents the label of each circle and the label of each grid line in the horizontal direction of the square on the right. D represents the diameter of each circle and the distance from of the square on the right to each grid line. Features - Color: Transparent. - Material: Glass. - Size: 1.80 x 1.80 x 0.20cm/ 0.71 x 0.71 x 0.08 inch. - The 0 line divides the rectangles into two squares on the left and right, with the particle counting area on the left and the length measurement area on the right. - The square on the left is divided into three parts in the vertical direction and two parts in the horizontal direction. - Six small rectangles are formed, which is convenient for counting particles in a certain area. - The square on the right is equally divided into three parts in the vertical direction, and into several parts in the horizontal direction. The upper part of each grid line is engraved with O, 4, 6, 8, 9...13 and other labels. - On the upper and lower part of the rectangular grid, there are several different sizes, but the upper and lower corresponding circles, the upper part is a hollow circle, the lower part is a solid circle, each has a =1, 2, 3...9, which can be used Quickly determine the diameter of dust. Package list: 1 x eyepiece