Concise ruler circular slide rule Stadia 100850. It is a slide rule for engineers who is equipped with SIN/COS/COS square measure for stadia survey and can perform height difference and horizontal distance calculation. Back side: General multiplication and division and trigonometric functions and percent gradient calculation for alidate fractionation.Scale: D, SIN COS, COS2 (square) (front) / D, C, C', S, T1, T2, ST (back). Special storage case, instruction manual included. International Buyers - Please Note. The item "Concise ruler circular slide rule Stadia 100850" is in sale since Monday, March 15, 2021. This item is in the category "Collectibles\Science & Medicine (1930-Now)\Engineering\Slide Rules". The seller is "kandyjp" and is located in Kanagawa. This item can be shipped to United States, all countries in Europe, all countries in continental Asia, Canada.