Proportional divider 7.5” Alvin 450 proportional divider with adjustable, replaceable steel needle points. Proportional dividers are used to transfer measurements from one scale to another. The proportional divider is used to make a drawing larger or smaller called scaling. Another function of a proportional divider is to divide lines or circles into equal parts. A proportional divider has two legs the same length that are pointed at each end and held together with a movable pivot point to adjust the ratio. By adjusting the pivot point, you adjust the leg lengths therefore creating a ratio for scaling a drawing up or down. the position of the pivot, you can adjust the lengths of the legs on opposite sides of the pivot so that the ratio between them is equal to the ratio between two scales. A useful tool for art, drawing, drafting, and design where scaling and ability to divide lines and circles equally is needed – 7.5” Alvin 450 proportional divider.