John Deere Windrow Hay Moisture Tester - SW07140. Moisture Tester - WINDROW HAY MOINTURE TESTER. Test results within 30 to 60 seconds. Measuring range from 13% to 70% moisture. Accurate to within 2% to 4%. Easily test windrow hay in a five gallon bucket prior to baling. This is a OEM John Deere part. Thanks for looking!