SAFE (make) Seatbelts

[Dreadnought]

Did anyone else,s 710k come with some seatbelts made by a company called SAFE. I have never seen belts like this before and I admit it. I cannot for the life of me work out how they work. (some parts were bagged up when I got the Pinz, other parts were bolted in, (but my wife took them out and I didn,t see how they fitted and she can,t remember)). I can see how the lap strap tightens but that,s as far as I can get with this puzzle, they are Grey Webbing and look well made. (The two front seats are fitted with modern black webbing intertia reel belts).