I bought this for my RTV900 2006 Worksite model after I found mine broken at the terminal:
Amazon.com: HVACSTAR Water Temp Sensor 31351-32830 for Kubota M4030 M4700 M4900 M5030 M5400 M5700 M8200 M9000 M95SH BX22D BX23D RTV900G R420S R520 ZD18 ZD21 ZD28 ZD321 ZG332P ZP330P : Automotive
Buy HVACSTAR Water Temp Sensor 31351-32830 for Kubota M4030 M4700 M4900 M5030 M5400 M5700 M8200 M9000 M95SH BX22D BX23D RTV900G R420S R520 ZD18 ZD21 ZD28 ZD321 ZG332P ZP330P: Engine Temperature - Amazon.com ✓ FREE DELIVERY possible on eligible purchaseswww.amazon.com
It's the same part number as the Kubota part number.