The core wraps around the hem and holds it in place. You can adjust the length in 4cm increments just by folding! Simply "roll in" the thick hem with the sewn-in "core" to the inside, and anyone can wear it at the perfect length right away! The flexible core firmly holds the hem, so the pant legs won't ride up, which is convenient. Also, the stretchy fabric makes it incredibly easy to wear. These straight-leg pants are easy to match with any top, making them a convenient choice. These will be folded and shipped.