The rubber O ring is what holds them close. You just roll the O ring up in the grove and then slide the blades forward and you can feel them pop into place and then they are held in good. When you shoot the O ring just slides back and in foam targets rolls down the shaft. They do not break since they are not stretched open. The heads come with a extra set of rings and I have yet to have to go to the store and buy more. They do not break like the rear hinge style. When I practice I can have all the blades set on three arrows in a forty yard walk.