Nolan has a kit, VPS, for about $75 that will retrofit any Nolan N-100 or N-100e.
Helmets made after 9/04 need the VPS and a set of side plates to match your helmet.
Helmets made before 9/04 need the VPS, the side plates and a new clear shield.
The shield is on the outside of the clear lens and is about 1 1/2 " high. It works smoothly and is easy to flip up or down. I especially like the clear view at all times thru the lower part of the shield..especially at night when looking at the speedo/tach or other dash items.
