Is your rubber door gusset hard or torn and beginning to fall apart? 
Perhaps it is missing completely?
Just repainted the car and need to refresh the door rubbers?
Replace it with a genuine replacement part from Mercedes Benz.
 
Part shown as no 335 in the diagram attached.
 
Will suit the following MB vehicles:-
W108 Sedan       (1968 to 1972)
W109 Sedan       (1966 to 1972)
W110 Sedan       (1961 to 1968)
W111 Sedan (1959 to 1968)
W112 Sedan (1961 to 1965)
W114 Sedan       (1968 to 1976)
W115 Sedan       (1968 to 1976)
 
 
Original Part No’s:- 
A1099970181 
1099970181
A109 997 01 81
109 997 01 81
109 997 0181
109-997-01-81
 
Don’t not pay over $60.00 for the genuine part. Our price only $22.50.
NB:- this item is a New Old Stock or possibly low use second hand .