Product description: 1. Temperature and Humidity Functions: Temperature and humidity readings show directly. The upgraded version has an external sensor, which can place the sensor line outdoors, and can display indoor and outdoor temperature at the same time.(Sensing line length : 1.3 M) 2. Time Function: Besides the basic time display, these item also has alarm clock and calendar display (month and date) 3. The upgraded version has Memory Function: When pushing the button MEMORY , it could display the memory of temperature and humidity maximum and minimum (Note: This feature is only available in the upgraded version, not in the regular version) 4. Simple Design: With the little bracket on its back side ,it is easy to place and carry 5. Battery Operation: Require 1 x AAA battery (not include) HTC-1 Material: ABS Color: White+Balck Item dimensions: 103 x 93 x 21.5mm Measuring Temperature range: -10C~+50C (14F~+122F) Measuring Humidity range: 10%~99% RH HTC-2 Material: ABS Color: White+Balck Item dimensions: 103 x 93 x 21.5mm Measuring Temperature range: -50C~+70C (-58F~+158F) Measuring Humidity range: 1%~100% RH Type A Backlight Design with backlight, can be used in dark places With Temperature, Humidity and Time Functions Material: ABS Color: White Item dimensions: 78 x88 x 21mm Measuring Temperature range: -50C~+70C (-58F~+158F) Measuring Humidity range: 10%~99% RH Battery Operation: Require 2 x AAA battery (not include) Type B Material: ABS Color: White/Pink/Green Item dimensions: 43 x43mm Measuring Temperature range: -9.9C~+50C (14.18F~+122F) Measuring Humidity range: 10%~99% RH Battery Operation: Require 1 x 2032 button battery (not include) Package Include: 1 * Temperature Humidity Meter ( battery not include)