device 2 is preferably able to withstand ethylene oxide sterilisation and accordingly an encapsulated ac or rf identification tag 3 is particularly preferred the identification tag 3 may comprise a read only or a read write device the data held on the identification tag 3 may be pre programmed onto the delivery device 2 during manufacture if a read write device is used the laser device 1 may update the information on the identification tag upon connection and may for example record the date and usage of the delivery device 2 the information received by the laser device 1 is preferably displayed for the user on a display 4 which may be integral with the laser device 1 the information may be displayed for example as a series of messages and or warning s based on the data exchanged the laser device 1 preferably automatically interrogates the delivery device 2 either upon connection of the delivery device 2 to the laser device 1 or upon switching the laser device 1 on interrogation of the delivery device 2 at switch on ensures that the laser device 1 detects whether a new delivery device 2 has been attached and whether or not the delivery device 2.