This item used to be sold by Land Rover but seems no longer to be produced. We got a small stock left, maybe for a dozen cars. They were originally made for Series vehicles used in extreme dusty and rainy conditions.
They will fit newer 90's/110's with some easy modifications too.
Made from an aluminium channel and an overlenght rubber seal lip they are simply pressed between the upper door seal and the body of the top. That's all- no tools required. Modifications for newer vehicles: You have to shorten the aluminium channel just a bit.
They seem to work quite well as they suppress the gap that exists on almost all cars between the door and roof. No more dust inside and noise is reduced too. Prevents also the doors a bit from rattling.
Can also be used on the descending part of the door (B-pillar) with some modifications.
Price: 300.- FLux/piece. Those are the last one we know of. You need one piece for every door top and another one for each side if you wish to do them too.