Note that the Rolleiflex "3.5 E3" was produced parallel to the "3.5 F" and was the result of a demand for a Rolleiflex 3.5 F without build-in lightmeter.
In construction it is largely based on the 3.5F.

Production : from 1961 to 1965, about 5035 units

Taking lens:
Carl Zeiss Oberkochen Planar 1:3.5 f=75mm, Coated, 6 elements.
or : Schneider-Kreuznach Xenotar 1:3.5 f=75mm, Coated, 6 elements.
Combined lever (MXV) for Selftimer and M- and X-synchronization.

 This is a great camera at a really good price.