
Totally agree with the other review. This model is useless. The range means you can only use it with very powerful light sources. Even the sun in a tropical climate will produce little reaction. The level of customer service is terrible. I wrote to them that I would like to measure blue light emission from home devices and they recommended it. Now that it doesn't work they tell me to buy bilirubin. You agree to exchange it on the condition that I pay shipping both ways. Which in my distant case is $140. Strange.