Not sure...

But here is some information from my National Exec...

Other things to note:
Handles may get warm during use on stovetop, depending on amount of time cookware is on stovetop and heat setting being used. Handles will get hot in the oven. Always use a heat-resistant oven mitt or pad when handling hot handles.

The Steamer Insert from the Professional Cookware line can fit in the 8-qt. Stockpot available in the 7-Piece Executive Cookware Set. The Steamer Insert from the Generation II line can fit in the 4-qt. Covered Casserole available in the 5-Piece Set.

The Double Boiler still functions with the Executive Cookware 2- and 3-quart Saucepans.

In the 7-Piece Set, the 8-qt. Stockpot Lid also fits on the 10” Skillet.

12” clear view lid also fits the Stir-Fry Skillet

Titanium medallion could only be placed on round cookware pieces and not square. This is due to manufacturing. Square pieces will have a logo on bottom comparable to Roasting Pan with Rack.

Autograph II is the most up-to-date nonstick technology available by DuPont. We do not recommend using metal utensils. The difference between Autograph and Autograph II is overall durability.

The Executive Cookware should be the first to market with the titanium reinforced alloy construction. Other brands (Anolon) also have a titanium cookware line, but the titanium is in the nonstick exterior coating, not the alloy. This Analon product has not been tested by the Test Kitchens.

Most cookware is intentionally designed to be convex – the center is slightly higher and it slopes down to the edges toward the sidewalls. This is done because as the metal heats, it flexes slightly and pulls the center down, so ultimately it is flat. If the center were flat on our Pro (and most cookware), as it heats, it would become concave. The center would actually dip slightly lower than the sides and it can cause spinning. Thus, historically, most (basically all) cookware is designed to be convex – except for the Executive line, which is flat.