Quick Test UVB Sensor, Reptile UV Tester Heating Lamp Photochromic UVB Card Indicator，Available with UVB, Suitable for Sunglass Test & Sterilizing, Over 500 Times Reusable (2 Packs)

I use these to check on my UVB lights every few months. I have used these for a couple years now with success. My older ones still work fine, I have just temporarily misplaced them.The instructions are easy to follow (place under UVB light for 10 seconds) and the chameleon will turn purple if the lights are still putting out UVB.This is a good option for someone who wants to check their lights but cannot fork out $200+ for a solarimeter

Fast shipping works well.

Seems to work pretty well

In case you didn’t know, the UV bulbs lose its UV coating over time. Some say to replace every 6-months some say longer. Don’t play the guessing game and grab these to test your UV bulbs.

These are very easy to use, and help me determine the relative effectiveness of my new/old UV bulbs. My only concern is that they technically are activated by both UVB & UVC, while I'm specifically interested in strength of UVB for my turtle. Definitely good value for the money, and an easy way to test reptile bulbs for UV.

Sure the card turns purple under UVB but you don't know how much is actually getting to your little friend

I got these because they were fairly inexpensive, and I have a bearded dragon. Florescent tubes are pricey, but UVB is vital for the health of the animal. This is a fantastic way for me to verify that the tube is still outputting sufficient UVB to keep our little buddy happy. I guess I am trusting that it's doing what it says it is doing, but it doesn't change color under an incandescent bulb and does under the UV tube.

So this works, but works slowly. One card showed purple in a nice purple color. The other never gets better than a faint purple.

Funciona tal y como lo mencionan .

Fonctionne très bien

Would have been nicer if they sent a placard to gauge how strong the UVB is.

It works well.