When the temperature between in 20~25 Celsius，humidity between in 40~70%，the screen will display smiling face.<br />when humidity under 40% or over 70%，will show different pattern.<br />when temperature over 20~25 Celsius，humidity between in 40~70%，the screen will no display face pattern <br />100% ABS environmental protection material.<br />Dimension:L100*W100*T28MM.<br />Multi-function alarm clock with thermometer hygrometer， date， week，clock，memorial day reminder.<br />High quality backlight ，HD HTN Screen;Imported electronic component.<br />Can be stands on the table or hang on the wall.<br />Battery:need 2pcs 1.5V AAA batteries(it is not included，buyers should prepare by yourself).<br />Measurement range:0~60Celsius;32~140F;20~99%RH.