public static void addRing(MapleCharacter chr, int itemId, int ringId, int sn, String partner) {
        CashItemInfo csi = CashItemFactory.getInstance().getItem(sn);
        if (csi == null) {
            return;
        }
        Item ring = chr.getCashInventory().toItem(csi, ringId);
        if (ring == null || ring.getUniqueId() != ringId || ring.getUniqueId() <= 0 || ring.getItemId() != itemId) {
            return;
        }
        chr.getCashInventory().addToInventory(ring);
        chr.getClient().getSession().write(CSPacket.sendBoughtRings(GameConstants.isCrushRing(itemId), ring, sn, chr.getClient().getAccID(), partner));
    }