if it wasn't welded in i'd say it looks a lot like corrugated cardboard.....
but its probably not, as it does appear to be welded then it appears to be a punched out screen with probably nothing behind it. it can't have any sort of repackable material as one end is welded and the other end is smaller than the welded end so you wouldn't be able to pull anything out that could be inside
so...it seems that it only has that screen as a sort of interrupter/noise killer and probably does fcuk all
some of the others that were advertised on that ad page would be better as they are the longer wrapable type, which not only do a reasonable job of quietening/getting through inspection but are rewrapable when the packing eventually burns out
another old trick with the repackable types was to wrap chicken wire round the baffle tube, not as quiet as fibreglass but lasts a long time
