Ray-JrMALL Mini Digital Temperature Humidity Meter Gauge Thermometer Hygrometer LCD Degree Celsius(C) Display Black For More Accurate Readings, Please Wait Several Seconds After Opening It. &gt;Wide Usage: Applicable for living room house decor, portable tour temperature monotor, fish tanks, pet box, drying box, cigar humidor, medical incubator, etc. &gt;Wide temperature testing range: -50 to 70 Celsius degree Humidity testing range: 1% to 99%. High temperature accuracy:  1. &gt;Super Tiny/Lightweight: dimension : Around 1.9"*1.1"*0.6"( 4.8 x 2.8 x 1.4 cm) Lightweight: around 20g; Power Supply: 2 x 1.5V button cell(included), Big LCD size: 1.8"*1.1". &gt;High Temperature and Humidity Sensor: Monitor the condition (Temperature , Humidity ) of the Environment Easily and Quickly, Degree Celsius (C) Display Only. Small size and lightweight, easy to carry on anywhere you go. &gt;Note: For this product, the normal tolerance of readings is 1-2 degrees. When you remove the battery to re-install, pay attention to the installation in the correct position, so that the battery protruding piece, resulting in difficult to close the back cover.