Easy to Test：Just place the testing card 3.5 inches away from the lamp and wait for 10 seconds.
Cover Testing：Cover the test card with your thumb，when the shows colour difference between the thumb-covered and non-covered areas on the testing card, means that the UVB bulb is working normally.
Recyclable Times：Compatible with sunglass test & sterilizing，reusable 500 times. When not in use, you need to put into the card sleeve or store it in a dark place.
Campatibility：3.0 -10.0 UVB bulb and Fluorescent bulb.
