Features: The instrument has an LCD that can display the value of UVC irradiance. When the lamp's output drops to 70% of original readings,please replace it. Simply press and hold the push-button switch on the face of the unit. Aim the sensor window in the top panel of the meter directly at the UV source. Note reading on LCD and record if desired. To get more accurate data,please take several tests at the same distance and averaging. Compact radiometer,Uses imported UV photosensitive devices,Comes with an integrated UVC filter,Has good cutoff characteristics. Adopting high-precision digital AD,display accuracy is stable and accurate. Imported sensor,no stray light effect,Probe material,UV glass. Widely used for daily UVCtesting of all types of reptile lamps,Effectively help you choose the best angle and distance of your own bulb. Package Includes: 1x UVC Light Meter Specifications: Material: ABS Size: 100x78x58mm/3.94x78x58mm Response spectrum: = 220-280nm Measurement range: 0~ 2000uW /cm2 Measurement accuracy: 1uW /cm2 Response time: T 0.5s Measurement error: 10% Power consumption: 0.25W Power supply: 2XAA battery( excluded) note: Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors,the picture may not reflect the actual color of the item.