This is GT Racing's replica factory 911R Porsche window with closed louvers. fit into the original frame on 911 through 993 models These windows are vacuum formed with CLOSED louvers. They offer a perfect solution for the street car application by providing the 911R look without the chance for water getting into the car. For "Early" cars with "Pop Out" windows, you need to trim to fit as the "Pop Out" frame is slightly larger than non pop out window frames. These windows are sold in pairs.