Ceramic gas heater radiant brick insert 7 1/2" tall 2 3/4" w 1 5/8" deep vented

Description

This heater insert is vented on the back and on the sides, it has gray coloring added and has a flat top.  There are small notches on each bottom corner and it has the number 413 inside.  I cannot identify the brand, but it may be a replacement for R358 Inland.
This item came from the liquidation of a hardware store, and is new old stock.  They may have markings from the store, or have a slightly dirty look...it was an old store.
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!