TRUaire 290 Series Fixed Bar Return Air Filter Grilles. Sizes listed below are LIST SIZES -- opening size. LIST SIZE grille frame will slide into a 12x12 drywall opening. The actual outer size of the grille frame is larger.
Table of Contents. Benign paroxysmal positional vertigo (BPPV) is a problem with the nerves and structure of the inner ear that causes you to suddenly feel dizzy. You might feel like the room is spinning around in circles or that your surroundings are moving. This feeling is called vertigo..
1 Benign paroxysmal positional vertigo (BPPV) is the most common form of vertigo and is characterized by the brief sensation of motion lasting 15 seconds to a few minutes.2  It may be initiated by sudden head movements or moving the head in a certain direction, such as rolling over in bed. Vertigo may also be caused by inflammation within the inner ear (labyrinthitis or vestibular neuritis), which is characterized by the sudden onset of vertigo and may be associated with hearing loss. 2  The most common cause of labyrinthitis is a viral or bacterial inner ear infection.