National (Portable), Portex				Rex Typewriter Co., Fond du Lac, Wisconsin
				1918 the American Can Co. of Chicago took control of the company
				In the National Typewriter Co., Fond du Lac, Wisconsin assumed comtrol of the company
Models and s/n	Y	M	D	Remarks	Ref.
National No 2
up to 3000	starting 1916			Estimated from known serial numbers	-
National No 3 and "B"				Manufactured by the American Can Co. of Chicago, Model &qot;B&qot; for export	16
4000-15000	1919			Estimated from known serial numbers	4
Portex or National 5
15000-23000	ca. 1920			Estimated from known serial numbers	4,16
				Nickle plated models are known with serial numbers over 20000	-