A device includes a plurality ofringlets connected together to form a ring having alongitudinal axis. Each ringlet includes a firstelement and a second element. The first and secondelements each extend from a first end through acentral portion to a second end. The first andsecond ends are disposed at radially outer positionswith respect to the ring than the central portion.The central portion is longitudinally displacedfrom the first and second ends. The first andsecond elements are separated and spaced apart fromeach other at the central portions thereof and arejoined together at the first ends thereof and thesecond ends thereof. The ringlets are connectedtogether such that the first ends of the elements ofone ringlet are connected to the second ends of theelements of an adjacent ringlet.
