Car seat carriers are disclosed. A tubular retainer having a passageway extending therethrough has a substantially oval proximal section and a substantially circular distal section, the distal section for fittingly receiving the proximal end of the flexible tube. The temporary anchors are removed from the first layer to free the operative parts formed therein. The receivers can thus be localized in space. In addition, a fluid accommodating plate for accommodating therein oil is provided in the vicinity of an opening between the outer ring and the inner ring which lies on a side where oil exits. An end of the non-magnetic pipe on the side of the magnetic pipe is positioned on the side of a moving core relative to a facing portion of a fixed core that faces to the moving core, and on the side of the fixed core relative to a second end of a yoke connected to the magnetic pipe.