Protos
Models and s/n	Y	M	D	Remarks	Ref.
Portable
Protos
	1922			identical with Adler Model 7	4
Model E
up to 6000	1922-1924			exchangeable typelever-set	4+7
Protos Portable	1924			same as Klein-Adler 3 row keyboard machine, but larger and minor technical differences, casing and top out of aluminium	4
	1925			production of all Protos Models ended