Can't seem to find strap adjuster

[GHinNH]

I have looked and searched for too long, even McMaster, I cannot seem to find this "magic adjuster" used for quick adjust rifle straps.

I have made my own straps for a long time, and have webbing, hooks, slide adjusters you name it other than this mythical buckle.

The interweb is great as long as you know the name of what you're looking for, but alas I have not yet found the right combination of words.

Anyone...?