Before revision: By not using the elastic o-rings, the claims are that the wires freely slide through the slots without friction but this is incorrect as it simply allows mroe rotation or tipping of teeth before the bracket edges contact the wire resulting in friction.
After revision: By not using the elastic o-rings, the claims are that the wires freely slide through the slots without friction but this is incorrect as it simply allows more(and therefore some potential loss of precision of movement) rotation or tipping of teeth before the bracket edges contact the wire resulting in friction.