Ceramic heater radiant brick insert curved 3 1/2" wide

Description

These are used in heaters...but I do no know anything about them, and cannot find any information (so if you can identify them for me I would appreciate it).  All I know is that they are related to heater inserts.  There are two colors available:  the natural and also multicolored.  They look like a miniature fret or flame protector, guard...not sure.  The embossing says Wiederhold Pat 446365; the store had written 458 on some of them.
Measurements from one radiant to the next can vary slightly, as these are molded and fired ceramic; and they sometimes have slight flaws or chips which do not affect the use.
Price is for each one, but shipping for each additional one ordered reflects an economical combined shipping cost.
This item came from the liquidation of an old hardware store, and is new old stock.  However, it may have stock number markings on the radiant, from the store. Some of these have a dirty appearance...it was a very old store.  Please look at the photos carefully to be sure this is exactly what you need.
Please ask if you need more information, and thanks for looking.
Most of my items are pre-owned, usually from estate sales, so I try to describe them accurately and show flaws in the pictures.  Any props in the picture, such as easels, ruler, or backdrops are not included.
Please contact me if you have any issues with your purchase and I will do my best to resolve it.
Thank you for looking!