Zyliss, I have an older model, but this one works the same way. The other ones some folks have mentioned work on the same principal, they cut through the seam.
My wife likes the old Swing A Way better, but she's always worried about the sharp edges. Like........Duh
The desert is a true treasure for him who seeks refuge from men and the evil of men. In it is contentment In it is death and all you seek (Quoted from "The Bleeding of the Stone" Ibrahim Al-Koni)