PAPRs, or powered air purifying respirators, are ‘positive pressure’ respirators that supply purified air to the headpiece and push HEPA (high-efficiency particulate absorbing) filtered air away from the face because they do not have a tight seal to the face.
A medical evaluation is not required prior to use since it is not a tight-fitting respirator.
There are several models, types, and manufacturers available, but almost all will have a removable hood/headpiece (with or without a shroud that can cover the neck area), a connector hose, battery pack, and HEPA filter that usually straps around the waist.
PAPRs are reusable and should routinely be cleaned and disinfected between uses and users.