[R-390] Dittmore&Freimuth mechanical filter

[Heinz Breuer DH2FA]

Hello,

a friend's jukebox revealed a R390A style mechanical filter with markings:

Dittmore&Freimuth
SM-D-243863
S/N:013
No: DF-455-BP-2-CB

I have not yet tested it but I guess it is a 2kc filter. Did 
Dittmore&Freimuth make their own mechanical filters or is it a Collins 
OEM product?

vy 73 Heinz DH2FA, KM5VT

PS: I am looking for a Helena Rubinstein filter? hihi