The flexible access authorization feature for wireless telecommunication systems enables network operators andor service providers to dynamically authorize a user to receive services for which the subscriber has not previously subscribed or which are not supported in the user’s home network. The plug includes a polymeric body having a plurality of integral projecting studs which have a snap fit engagement with an inward radial protrusion of the bore within the hydraulic valve. The visual monitoring system is responsive tri-axially to command signals received via a patient controller connected to the network. In yet a further aspect, the device is a sensor device.