To trilipse, this tool is a relic of world war two, it was part of an SOE spys kit. It is like a piece of bamboo cane but metal, 6mm wide 300mm long, split along its length, joined just at the handle, somewhat like a "rat tail file". You put the stem through the slight opening at the corner of the flap all the way through to the other opening opposite, putting the split rod on each side of the notepaper, squeeze the rod and turn it to roll up the letter around the rod then pull it out. That is my explanation please tell me if you follow it?