An apparatus comprising a first curved band portion and a second curved band portion. The first curved band portion has a first end, a second end, an inner curved side and an outer curved side. The first curved band portion defines a passageway between the first end and the second end of the first curved band portion. The passageway has a first opening. The second curved band portion has a first end, a second end, an inner curved side and an outer curved side. A motion-restraint portion is proximate to the first end of the second curved band portion. The first end of the second curved band portion is insertable into the first opening of the passageway of the first curved band portion. The first curved band portion has a range of motion within the passageway of the second curved band portion.