The phrase "double gussets" refers to the extra fabric panels sewn into the sides of a garment to offer more room and flexibility, especially in areas like the crotch or armpits. It helps improve comfort and mobility in clothing. Full definition
Our one - size diaper covers can snap to fit babies from 9 - 35 pounds and are made of 2 layers of soft wipeable PUL with double gussets around the legs. (mommyscene.com)
That being said, I know a lot of moms that LOVE double gussets on a diaper. (themonarchmommy.com)