These were designed to replace the original mounts as these were found to be difficult to use and not very stable in use. These mounts not only provide easy fitting and removal of aero screens, but also keep the screens lower on the dash therefore more effective. Furthermore, these are rigid, and less likely to vibrate. These can be fitted either on top of the cockpit roll, or underneath.
The 'drill chuck' action grasps the two uprights of each aeroscreen. This means that the aeroscreens can be removed quickly, and then the domed blanks can be fitted to give a pleasing finish, unlink the standard items, which look out of place, when the aeroscreens are not fitted.
A safety point is that ideally, you should not drive with the aeroscreens fitted and the windscreen in place, at the same time, as this can distort your vision, especially in night time driving. We have seen many Morgans with this hazard, purely because of the difficulty of removing the aero screens, no longer a problem with these!