A lamp includes a main body and a removable cover, and the main body includes a lamp housing, a printed circuit board (PCB), at least one light emitting element, and a threaded base. The lamp housing defines a socket configured for receiving the PCB and the at least one light emitting element, and the PCB is electrically connected to the at least one light emitting element and fixed in the socket. The removable cover includes a light-transmission portion and a connection portion, the connection portion connects to the end of the lamp housing with the socket, and the light-transmission portion is opposite to the socket. Light from the at least one light emitting element is emitted from the light-transmission portion.