With further reference to FIG. 3, the main housing 10 is hollow and has a receiving chamber 11, two end holes 12, two outer side surfaces 13 and two pivoting parts 14. The receiving chamber 11 is defined inside the main housing 10. The two end holes 12 are formed through two opposite ends of the main housing 10 and communicate with the receiving chamber 11. The two outer side surfaces 13 are oppositely defined on the main housing 10. Each of the outer side surfaces extends between the two end holes 12. The two pivoting parts 14 of the main housing 10 are formed on the outer side surfaces 13 of the main housing 10 respectively and are both located along a first axial line. The data storage module 20 is mounted in the receiving chamber 11 of the main housing 10 and has a first electrical connector 21 and a second electrical connector 22. The first electrical connector 21 and the second electrical connector 22 protrude out of the main housing 10 through the two end holes 12 respectively. In the preferred embodiment as shown in the figures, the first electrical connector 21 is, but is not limited to, a Universal Serial Bus (USB) Type-C connector and the second electrical connector 22 is, but is not limited to, a Lightning connector. In other embodiments, each of the first and second electrical connectors 21, 22 may be an electrical connector, such as a USB Type-A connector, a USB Type-C connector, a Lightning connector or the like, that is for transferring data, and the first electrical connector 21 and the second electrical connector 22 are different kinds of electrical connectors. The first protective swivel 30 is substantially U-shaped, and has two inner panels 31, two inner pivot parts 32 and two outer pivot parts 33. Each of the inner panels 31 is elongated, and has a first end, a second end, an inner surface 313, and an outer surface 314. The first end of the inner panel 31 and the second end of the inner panel 31 are oppositely defined on the inner panel 31. The first ends of the inner panels 31 are connected to each other to form a closed end 311 of the first protective swivel 30. The second ends of the inner panels 31 are spaced at an interval such that an opening end of the first protective swivel 30 is formed. The inner surfaces 313 of the two inner panels 31 of the first protective swivel 30 face each other.