The Kubota W21TS09991 is an authentic OEM thermostat designed to precisely regulate engine coolant temperature. With an 82°C (180°F) opening temperature, this critical component ensures optimal engine performance and prevents overheating in a wide range of Kubota machinery. It is a direct replacement part for numerous Kubota compact tractors (BX, B, L series), utility vehicles (RTV series), and zero-turn mowers (ZD series), guaranteeing reliable cooling system function and engine longevity.