The round rubber ring K 43572 is an important elastomeric sealing component designed for the pilot valve K 43610 used in the starting-air control system of the Adriadiesel/Jugoturbina/Zgoda/Sulzer ZV40/48 engine. Its primary function is to provide an effective seal between the corresponding components of the pilot valve, helping prevent unwanted compressed-air leakage and maintain the pressure conditions required for accurate pneumatic control. As part of the pilot valve assembly, the round rubber ring supports reliable pressure separation and contributes to the consistent transmission of pneumatic control signals that coordinate the operation of associated starting-air valves. Its sealing performance depends on correct dimensions, suitable rubber hardness, elasticity, compression characteristics, and compatibility with the operating pressure, temperature, and surrounding media. During service, the K 43572 round rubber ring may be exposed to repeated pressure fluctuations, vibration, compression, temperature variations, and material aging, potentially resulting in hardening, cracking, flattening, swelling, or loss of elasticity. During maintenance or overhaul, the ring and its corresponding sealing surfaces should be inspected for wear, deformation, contamination, surface damage, and deterioration, with replacement carried out according to the manufacturer's specifications. By maintaining effective sealing within the K 43610 pilot valve, the K 43572 round rubber ring contributes to stable pneumatic control, reduced compressed-air losses, reliable actuation of associated starting-air components, and dependable long-term starting performance of the ZV40/48 engine.