Disclosed herein is an aluminum hydroxide having specific characteristics, and a tire tread rubber composition and a pneumatic tire employing the aluminum hydroxide, which allow grip performance and abrasion resistance to increase and rolling resistance to decrease and are superior in processibility. Displacement of the coil relative to the armature is generated by forces corresponding to magnetic field lines generated by the coil, concentrated in the armature and the yoke, and directed essentially through an airgap situated between the armature and the yoke. Each optical fiber connection between nodes includes at least three channel groups with different priority levels for restoration switching in response to a connection failure. The memory control circuitry is configured to set a clock based on the first signal. Said aim is achieved whereby the contact pieces which may be displaced relative to each other are moved with a relatively high speed during a first phase of the separation process until about \xbc to \xbd of the ultimate separation and are brought to the given ultimate separation during a second phase with relatively low speed.