Review on 🔌 Parker Hannifin 6316 62 00WP2: High-Quality Polymer Body Bulkhead Union Fitting - 1/2" Push-to-Connect Tube x 1/2" Push-to-Connect Tube by Alisa Romero

I should have noticed in the picture but this "bulkhead" fitting has nuts on both sides; Therefore you cannot use it for a waterproof (or airtight) application as water (air) will seep through the threads. If you just need to make a good, solid fitting that goes through the wall, it's well made and will work, but you can just use a spigot instead.