Greisinger gmh 3350 thermo hygrometer and flow rate meter greisinger gmh 3330 the greisinger gmh 3330 is a thermo hygrometer and flow rate meter and is suitable for the rapid measurement of humidity and temperature making it ideal for applications in buildings factories and warehouse environmentswhats in the boxgreisinger gmh 3330battery 9v blockuser manual greisinger gmh 3330 thermo hygrometer