Type A HEPA disposable paper vacuum bags.
Koblenz bag number 45-0766-1 and 4507661.
Examples of Koblenz upright vacs that use the Type A bag includes:
U-75 ZA,U-110ZA, U-310ZA, U-510ZA, U-610ZA
The bags have filtration efficiency of 99.97% at 0.3 micron particle size
They help retain pollen, bacteria, dust mites and allergens.