E12 The HEPA class is a specification used in the European Union (EN 1822:2009). It defines several classes of HEPA filters by their filtration efficiency. The class starts with E10 (85% efficiency) till U17 (99.999995% efficiency).
Retention 99.5% Retention defines the (local) efficiency of a HEPA filter. Filters are rated on their ability to remove particles of a specific size from the air. The definition of retention is the percentage that a filter will stop certain particles from the air.
This filter ensures that the air blown out of your Vacuum Cleaner is filtered very precisely. Even the smallest dust particle will remain in the filter, giving the room that nice and clean feeling. Moreover, this is literally a breath of fresh air for people with allergies.