The lightest model in flight, adjustable propellers, developed on the basis of the successful KA-1 profile. By optimising the profile slimming of the propeller, the diameter of the propeller was increased to 1.700 mm. The change in the construction of the propeller blade and consequent modifications to mechanical parts result in better flight parameters than in the case of type KA-1, a lower weight, and more comfortable operation. It is used for many types of modern planes.