Jean Genie has many uses.  The first and most important is that all you need to do is place the Genie over the jeans and mark the hem allowance.  Obviously there is a little more to that and you will see what I mean by watching the video.  So why did I create it for this purpose?  I can't tell you the amount of times a person came to me with jeans that had been cut too short.  And this usually happened because they forgot about the seam allowance and cut on the new length mark.