The second, newer one accommodated the slightly larger skillet or Dutch oven of the A series pan design which had straighter lines than the flared shape of the P series which was what the first heater base was made to hold. The position of the Bakelite handles on the first design held the skillet steady, but the pop in fence was needed to keep the Dutch oven steady on the base. It was too tight to allow clearance for the A style pans, though. CU said it had a small capacity for an electric skillet and weighed more than any other. The Electromatic Dutch oven is perfect for making matzoh ball soup because of the glass lid and extra surface area afforded by the square shape. The control gives the perfect simmer without boiling, unlike most plug in electric pans where the heating element is cast into the base of the pan. With the glass lid, I can watch the knaidlach swell and make sure the water is not boiling. The precise heat control does not let the soup return to a gentle boil until the dumplings have completely cooked and swelled to their full size which is important.
One nice thing about the older style heater base is that it gives temperature ranges that correspond to the five heats of fixed heat controls so if you don't have a recipe giving a thermostatic temperature setting, you can have a guideline as to what setting to use to match what you would use on the range.
