The price is for just the Glass Shade only.
Prismatic glass shades are made from cast glass characterized by small ridges on the outside surface. It is these ridges that allow the light to be evenly distributed around the fitting and obscure the light bulb. With a history as long as electric light, prismatic light fittings have a timeless appeal.
Specification
Medium Railroad 130mmH 305mmDia 60mm Internal Hole
Large Railroad 165mmH 380mmDia 60mm Internal Hole