The thermometer Work and Application: The thermometer have three hands, the black hand indicating real temperature, the red hands indicating thedailyhighest temperature, and the blue hands indicatingthe dailylowest temperature. The red and blue hand were fixed on the lens with setting knobs. You can reading the real temperature by the black hand.The black hands will push theredhand to the reading of highest temperature when the real temperature is rising.The black hands will push thebluehand to the reading of lowest temperature when the real temperature is downing.Simply state, when the time nearby 14:00PM the temperature will rising to maximum of that day. when the time nearby 4:00AM the temperature will downing minimum of that day. We advise you reading the thermometer least one times every day, and recording the highest and lowest temperature at 7:00AM or 20:00PM. After recording, turn the knob on the lens and setting the red/blue hands to be align with black hand. The methods of hands setting, first turn the big knob and setting the red hand to be align with the right side of black hand, after that turn the small knob and setting the blue hand to be align with the left side of black hand, With back hole for wall mounting. Color: as shown Style: Standing Station Max Measuring Temperature: 49C & Under Power Type: None Display Type: Analog Display Size: 4.0 - 6.9 Inches : Temperature Controller Usage: Indoor : Measuring range: -40~50C; -40~120F Resolution: 1C, 2F Accuracy:2C,+/-5F material: metal Unite Size:128mm X TH48mm Package Contents: 1 x thermometer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.