BEAM Central vacuum inverted bag filter with gortex coating.  BEAM filters come with either a 11" or 14" diameter.  The 11" filter comes in two lenghts. This is the medium 11" filter for the following models:
 
For BEAM Models: 189, 193, 197, 199, 750, 775, 2100, 2775
 
Part #110356 or 110385