Abstract: A connector unit is disclosed which comprises a shaft, a plurality of collet fingers, and a sleeve. The plurality of collet fingers are peripherally positioned against the generally cylindrical outside surface of the shaft adjacent the lower end of the shaft. The sleeve has an upper end, a lower end, and a generally cylindrical inside surface positioned peripherally around the shaft. The sleeve is provided with a radially inwardly extending annular flange extending from its inside surface between its upper end and its lower end which forms a seal with the generally cylindrical outside surface of the shaft. An upper annular chamber is formed between the generally cylindrical outside surface of the shaft and the generally cylindrical inside surface of the sleeve above the radially inwardly extending flange and a lower annular chamber is formed between the generally cylindrical outside surface of the shaft and the generally cylindrical inside surface of the sleeve below the radially inwardly extending flange.