Probably from the 1920's. Original cord was replaced with an orange 110. Does have some blemished areas near heating filament as reflective area appears to be chipping (possible rust spots). Surface rust areas on some parts.
Looks like it could be used as a fireplace insert. Measures 25" Wide in front and 18" Wide in back, 12" Deep, 14" Tall front legs and 18 tall in back. Package dimensions for UPS are approximately 28" W x 22" D x 22 T and 24lbs.The item "RARE WORKING electric heater Marks Mfg Co Chicago, cast iron, fireplace insert" is in sale since Thursday, June 25, 2020. This item is in the category "Antiques\Architectural & Garden\Fireplaces, Mantels & Fireplace Accessories". The seller is "boileranimal182" and is located in Newport, Oregon.
This item can be shipped to United States.