Abstract: An alarm system for a cycle comprising an electrically conductive cable adapted at its ends to be secured to a housing assembly that is in turn mounted at a suitable location on the frame of the cycle. Control circuitry connects the cable to a warning device and is operable in response to detection of an electrically conductive contact with the cable to activate the warning device for a preset length of time. The housing assembly includes a hollow casing body and a closure plate that is secured to the casing body by screw members which are connected to the control circuitry and which function as switches. In response to a removal of any one of the screw members a predetermined distance the control circuitry activates the warning device.