This is double injection molding/ two shot molding. It is shaped once-through by two materials(white and transparent). This process allows for clear windows, colored lettering or graphics or just a decorative and stylish appearance to your part. 

This process has been used for keycaps and buttons on telephones and other products for many years. The molded-in graphics are embedded in the part and will not wear off with use. Clear sections can be utilized with back lighting for readability in dim or dark applications. 

Parts from double injection molding can be designed in arrays to reduce assembly labor and eliminate defects from improper orientation common with individual parts. 

Colors are easily changed to allow using one mold to produce parts with different appearances for product differentiation. 

Selective plating is also applied to enrich the decoration.