| 摘要 |
A surveillance device is disclosed which includes a housing (12) defining a space (44) for receiving a signal emitting member (42). The device includes attachment means (16) for attaching the housing to an article. A signal emitting member (42) is located in the space (44) defined by the housing (12) and sealing means (14) seals the housing (12) towards its outside to prevent unauthorised removal of a signal emitting member (42) located inside the housing. The signal emitting member (42) may be an acoustic-magnetic member. |
