Reason being they can be taken apart and the spring swapped out. Find an Ace hardware with a good spring selection and you can make your own adjustable valve. Takes longer but it’s a ton less money than the adjustable one.
But even after that I ended up buying one of these. I got the PCV set up right, but it still pulled too much oil
I plumbed it with this and some AN like to the valve cover. Spent a crap load anyway. Although the fancy adjustable PCV would have still needed it on my car
