Three of these are Pittsburgs and one a New Lexington. Can you pick it out? The top left is the New Lexington. The top right is a Pitt U-746A. The two on the bottom are Pitts that fall somewhere in the Redlands U-746 family. The bottom left sits flush on all three skirts. The bottom right sits on the inner most skirt and has a tiny crown and a full 7" diameter like the New Lexingtons. All 3 Pittsburgs display Pitt characteristics including the classic unglazed pinhole with the dime sized indented circle at the top. The NL has a sloppy top to the pinhole with an irregular gap. The lower right has a partial date code APR 6 ??. All four units have a glazewelded inner most skirt .