Sheet Steel Products Co. were early truck cab manufacturers (1920) whose product was sold in closed, semi-closed and open styles.  (July 15 1920 CCJ ad pp 292)

A complete line of open seats and dashes, semi-closed and fully closed cabs for motor trucks, in steel construction of the highest standard.

For more information please read:

G.N. Georgano & G. Marshall Naul - The Complete Encyclopedia of Commercial Vehicles

Albert Mroz - Illustrated Encyclopedia of American Trucks & Commercial Vehicles

Denis Miller - The Illustrated Encyclopedia of Trucks and Buses

Tad Burness - American Truck Spotter's Guide, 1920-1970

Tad Burness - American Truck & Bus Spotter's Guide, 1920-1985

Robert M Roll - American trucking: A seventy-five year odyssey

David Jacobs - American Trucks: A photographic essay of American Trucks and Trucking

David Jacobs - American Trucks: More Colour Photographs of Truck & Trucking

John Gunnell - American Work Trucks: A Pictorial History of Commercial Trucks 1900-1994

George W. Green - Special-Use Vehicles: An Illustrated History of Unconventional Cars and Trucks

Daniel D. Hutchins - Wheels Across America: Carriage Art & Craftsmanship

Ronald G. Adams - 100 Years of Semi Trucks

Stan Holtzman - Big Rigs: The Complete History of the American Semi Truck

Stan Holtzman & Jeremy Harris Lipschultz - Classic American Semi Trucks

Stan Holtzman - Semi Truck Color History

Donald F. Wood - American Beer Trucks

Donald F. Wood - Beverage Trucks: Photo Archive

Donald F. Wood - Commercial Trucks

Donald F. Wood - Delivery Trucks

Donald F. Wood - Dump Trucks

Donald F. Wood - Gas & Oil Trucks

Donald F. Wood - Logging Trucks 1915 Through 1970: Photo Archive

Donald F. Wood - New Car Carriers 1910-1998 Photo Album

Donald F. Wood - RVs & Campers 1900-2000: An Illustrated History

Donald F. Wood - Wreckers and Tow Trucks

Gini Rice - Relics of the Road

Gini Rice - Relics of the Road - Impressive International Trucks 1907-1947

Gini Rice - Relics of the Road - Keen Kenworth Trucks - 1915-1955

Richard J. Copello - American Car Haulers

Niels Jansen - Pictorial History of American Trucks

John B. Montville - Refuse Trucks: Photo Archive

Bill Rhodes - Circus and Carnival Trucks 1941-2000: Photo Archive

Howard L. Applegate - Coca-Cola: Its Vehicles in Photographs 1930 Through 1969: Photo Archive

James T. Lenzke & Karen E. O'Brien - Standard Catalog of American Light-Duty Trucks: 1896-2000

James K. Wagner - Ford Trucks since 1905

Don Bunn - Dodge Trucks

Fred Crismon - International Trucks

Don Bunn - Encyclopedia of Chevrolet Trucks