KL-1 USSR MECHANICAL CALCULATOR LOGARITHMIC Circular Slide Rule NOS 1967. This rule is made by the Moscow control devices for the Ministry of Instrumentation of the USSR in 1967. Circular logarithmic slide rule "KL-1" is intended for solving the most occurred mathematical operations. Calculations of circle square and finding of trigonometric functions of a sine.Finding of trigonometric functions of a tangent. Finding inverse trigonometric functions (of sines and tangents). Calculation of the area of a circle. The logarithmic rule consists of the body with two knobs, two clock faces, one of which is going round by means of a knob with black point, and two arrows going round by means of a knob with red point. The rule is in good working condition. The item "KL-1 USSR MECHANICAL CALCULATOR LOGARITHMIC Circular Slide Rule NOS 1967" is in sale since Thursday, May 10, 2018. This item is in the category "Collectibles\Science & Medicine (1930-Now)\Engineering\Slide Rules". The seller is "rarest_watch" and is located in Mariupol. This item can be shipped worldwide.