Many LEDs, particularly those at 670 nanometers, are not what they claim to be in terms of quality and authenticity, and their performance can degrade over time.

“poor in terms of how they're put together, first of all, the value of the components. You when you get an LED, you know, an LED is like buying a car. You can buy a bad car or you can buy a very good car. A lot of the LEDs are not what they say they are. Certainly when it comes to things like 670 nanometers, which is popular, they're hard to get. So, they're not what they say they are. And very often, they're not what they say they are a year down the road when they've been on and off for a long period of time.”