Provided is a chromium-free metal surface treatment agent excellent in rust inhibitive performance which can be used in a surface treatment of metal products, in particular, galvanized metal products. The principle of magnetic adsorptive is used to combine the Bluetooth headset with the speaker base. The RE middleboxes may employ max-match-based RE techniques or chunk-match-based RE techniques. A network of automatic card handling devices may include a plurality of automatic card shufflers. The failure of two wheels can be accommodated but operation may then be in degraded mode. The conveyance apparatus has first and second conveyance rollers.