The two halves are held together with springs, there is a piano hinge placed on each side. The pin on the hinge is removed , the two hinge parts act like interlocking teeth that line up the two halves. There is an expansion spring connected to the top and bottom halves on each side. I can push my hand through and the gauntlet spreads open, once my hand is through, the spring snaps the two halves shut and the interlocking portions of the hinge keep the gauntlet aligned and prevent them from sliding apart. The springs keep the gauntlets closed tight enough and keep them from moving around on my arm.