A closure device includes a first ring structure having a first distal portion and a first medial portion and a second ring structure having a second distal portion and a second medial portion. The first and second distal portions are movable between an open position, where the first and second distal portions form an angle relative to one another for receiving target tissue therebetween, and a closed position, where the first and second distal portions are drawn toward one another for gripping the target tissue. The device also includes an anvil about which the first and second medial portions are formed. Either one of proximal motion of the anvil relative to the first and second rings or proximal motion of the medial portions relative to the anvil causes the first and second distal portions to move into either one of the open position or the closed position.