An SVC cluster manages a plurality of storage devices and includes a plurality of SVCs interconnected via a network, each SVC acting as a separate node. The handle comprising at least part of the wall of the chamber, which is sufficiently rigid. Because the multi-user signals can maintain orthogonality, the performance degradation caused by the multi-user interference can be prevented. A shallow trench isolation region is formed between two separated source sections of the source region and between two separated drain sections of the drain region. 05 to 10 parts by weight on the basis of 100 parts by weight of the polyoxymethylene resin, and the ratio of by weight in the composition being 991 to 7030.