Jean Genie has many uses. The most common is the ability to help sew over thick seams, as part of the process to create a professional jeans hem on a domestic sewing machine.
The second is to use it anytime when sewing thick seams. It could be stretch fabric, double thickness cottons or even leather. The magic of the Jean Genie is its versatility.
It can be purchased here as an individual piece, or it can be purchased by buying a limited copy of my book Clothing Alteration Secrets Revealed.