The later models have a larger focusing screen compared to the earlier models:
Later models are mainly 64mm*68mm
Later models include Rolleflex 3.5-E2, 3.5E-3, 2.8E-2, 2.5E-3, 3.5F, 2.8F, Tele, Magic, Magic II, Wide Angle, Rolleicord Vb, basically all these come with removable viewing hood.
The earlier models are mainly 56mm*64mm
The earlier models include Rolleiflex 3.5, 3.5E, 2.8 (A), 2.8 (C),
2.8 (D), 2.8 (E), Rolleicord III, IV, V, Va
Source: http://www.mauropalmentieri.com/html/beattie/medioformato/rolleiflex.htm
Rolleiflex
Rolleiflex TLR (newer models) Notes:
Rolleiflex TLR (older models)
Rolleiflex SLX, SL66E, 6006-6008 |
TLRgraphy 
Reblogged this on Twins For Twins and commented:
Great read
I have one focusing screen with sizes 69x69mm (55x60mm inner)
Plastic with stamp of rollei mark
What camera could be?
Thanks! 😉