Cutting long rectangles from a roll of wrapping paper

This video shows you how to precisely cut a long rectangle from a roll of wrapping paper.

Online sources for the envelopener:
https://www.origamis... (based in the US)
https://www.origami-... (based in France)
http://supplies.brit... (based in the UK)
http://www.viereck-v... (based in Germany)
https://www.origamis... (based in Germany)