Unknown, possibly Waffen-SS (?) cuff-title (ie. 'Ärmelstreifen') entitled: 'H.F. Einsatz'. You can see one letter was removed straight before the "Einsatz". It should be a "H".
The armband is a (typical) SS-pattern, linnen-based example (having two rows of 7 silver-coloured strands) and was clearly used- and tunic-removed. One of the ends is a bit frayed whereas the other end shows an (off-factory) finished end. The armband has a total length is 42 cms. and shows some age, wear and/or staining. No reference could be found regarding this 'H.F. Einsatz'.