Waterproof is very important for LED grow light. JUNCTION BOX TOPIC. In the junction box, there are the input and output lines of the LED module, and the control line of the power supply. If moisture enters and the lead-in contact is poor, the light may not turn on. If you look carefully, you can see that there is a layer of waterproof rubber pad on it, so that when the cover is tightly closed, it can have a good waterproof effect.