These breather patches allow air to vent out of a headlight, but block moisture from coming in. This is a big help in preventing condensation from building up on the inside.
These come in packs of 32, the circle stickers are 20mm in diameter, or just over 3/4 inches. They are designed to be placed over a 1/2 inch hole. We recommend using four per lamp to provide maximum airflow.
To install, drill a 1/2 inch hole on your lamp. We recommend 2 along the top and 2 on the bottom, but you can choose anywhere that has a flat surface. Clean the hole and stick on the patch, holding firmly for 5 seconds to ensure good adhesion. That's it!