L. C. Smith Bros. & Corona Typewriter, Inc.
Frank S. Rose
Original Price: $45-60
Joe Sierer (Public Opinion, 14 Sep 1938), claims in an opinion article that "Corona made the first successful portable". The Corona Portable Model 4 was advertised as a private typewriter with big-machine features, and easy to learn to type. The middle advertisement to your left was retrieved via Google Books, https://books.google.com.