This HEPA bag is compatible with the Allergy Upright Vaccum and retired Symmetry models. Genuine HEPA media vacuum bags capture dust and allergen particles. 
 
These bags are made from cloth for maximum filtration and are HEPA filtered. 
Genuine Simplicity Part SAH-6
 
These bags are compatible with the following Simplicity models:

Sentry
5000 & 6000 series
Symmetry Entry (Part # S20E, S20EZM)
Symmetry Standard Classic (Part # S20SC)
Older Symmetry models with SYM in the part #

See Part # SMH-6 for other S20 models.