These are replicas of the ’66-’67 doors which had bolt-in removable window frames. You can install the factory internal parts to make them fully functional. In keeping with the simplicity of Broncos, we wanted simple wire window frames and side curtains to eliminate the internal roll up window hardware and associated weight. We offer soft windows to accommodate those wanting the simplicity or convenience of them! Our doors are very solid and hold up well. In the hinge area, I add extra layers of glass as well since this is a high stress area.