A magnetic head includes a pole layer, a first and a second shield disposed to sandwich the pole layer, and a nonmagnetic layer disposed around the first shield. The relaying apparatus has a reference time generating part that generates a reference time independently of the transmitting apparatus; and a network transmitting part that transmits both the real time information received from the transmitting apparatus and the reference time via the wireless network. The apparatus includes a pair of hanger assemblies which are pivotally secured to the saddle member and which extend downwardly therefrom for supporting a pair of footrests thereon. And after registration, when the particular action is sensed with the mobile device, the particular operation is effectuated. Various outer housing sleeves are disclosed including a structure split axially and a monolithic structure. The auxiliary wheel is adapted to maintain the stability of the wheel when the wheel is on a rotating state; moreover, the wheel can stop rotating when applying a force to the auxiliary wheel.