ADS, Flectcher did make a few ribs in the mid 80s. but didn't see a future in it and sold the moulds to Osprey who went on to make the Falcon series in 6.5 and 8.2m.
However I can't confirm if this is one of those ribs.
looks like fletcher radial .pvc bolt on tubes with pvc liners ,black toggles along outer edge double up as rubbing strake and sort of zip without slider to gain acess to inside of tube looked very clever when i visited fletcher factory early eighties but possibly to far ahead of their time, also a dispute between fletcher and the italian tube makers i think
