I’ve been a professional scuba diver for 30+ years, and I can tell you that there are some really good anti fog solutions on the market that actually work, I’ve used them on my dive mask for years, and you can apply it to the inside of your helmet shield and it will prevent fogging. I have a pin lock system on my helmet and I don’t even use it. I tried it for a while, but I found the solution to be a bit more convenient, and there’s nothing to obscure my view. Just letting anyone know who doesn’t have pinlock or would like to try a different option. The solution I’m using right now is called “spit”, it works as good as some of the others I’ve used, but there are a few more out there that work fairly well. If it says that it’s a military grade solution, it probably works well, unless it’s an imitation.