How do litter pickers/hand-grabbers work?

The hand consists of a fixed claw finger that is attached to the end of the rod, and another hinged claw finger which is on a spring hinge that causes the claw to fully open when no force is applied, the sprung finger is attached to the trigger by a length of cord of some kind, which is naturally relaxed and pulled taught by the trigger, at the other end it is attached to the hinged claw, the cord runs down to the claw inside the rod and wraps around the hinged point of the finger starting from that side that is beyond the hinge away from the end of the claw, and then wraps into the inside of the claw on that finger, such that when the chord is pulled taught the pickers claw is pulled closed, when you release the trigger the sprung hinge pulls against the chord returning the claw to open and the trigger to its unpressed position.