A Hygrometer is every lash artists secret weapon to keep their eyelash extension adhesive in line! If you are not using a hygrometer in your lash space you should be! Those days you wanna pull your hair out because the adhesive is acting “different” than the day before, here is why: Eyelash extension adhesives cure (turn from a liquid to a solid) from the moisture in the air. The best way to keep your adhesive working on point is to keep your humidity and temperature in a good range and to measure them with a hygrometer. Recommended room humidity on average is 40-60% (this can vary with different adhesives). Room temp: If you are comfortable in the room, your adhesive will be also. In cold temperatures your adhesive thickens, in hot- it becomes more runny so keep your room at a comfortable room temp, around 70-75 degrees Fahrenheit. Display temperature, humidity and time simultaneously Display in C or F Integral-hour alarm function Clock & Calendar function (month and date ) Memory of MAX & MIN measuring value 12-hour / 24-hour displaying Desk-top placing or Wall Hanging Temperature range: -50~ + 70 C ( -58 ~ +158 F ) Humidity range: 20%~99%RH Resolution: temperature: 0.1 C ( 0.1 F) humidity: 1% RH Power supply: 1.5V ( AAA size ) X 1(not include) Accuracy: temperature :± 1 C ( 1.8 F ) humidity :± 5 RH ( 40% ~ 80% ) Product dimension: 100 x 100 x 15mmStorage condition: -20 C ~60 C , 20~80%R