Patent ID: 7557706

Claim:
A seal including a first part including a shaft and a head at one end of the shaft, the shaft having engagement means in its end region remote from the head; an electronic circuit carried by the first part and including a radio frequency identification (RFID) transmitter and sensing means for sensing severance of the shaft of the first part, the circuit being in a normal state and configured to, upon sensing severance of the shaft of the first part, change into a warning state, the state change being detectable by means of an interrogation device compatible with the RFID transmitter; a second part defining a receiving formation for the shaft of the first part and having engagement means for irreleasibly engaging the end region of the shaft of the first part that has engagement means, via this engagement means, when received in its receiving formation, the second part forming a head at the end of the shaft of the first part remote from the head of the first part, when so engaged; a third part made of a tamper resistant material and including a shaft and a head at one end of the shaft, the shaft having engagement means in its end region remote from its head and the part defining therethrough a passage for receiving the shaft of the first part, the passage daylighting on opposite ends thereof in the head of the third part and in the end of its shaft remote from its head; and a part made of a tamper resistant material and defining a receiving formation for the shaft of the third part and having engagement means for irreleasibly engaging the end region of the shaft of the third part that has engagement means via its engagement means when received in its receiving formation, the part defining the receiving formation for the shaft of the third part forming a head at the end of the shaft of the third part remote from the head of the third part, when so engaged, the parts being shaped to provide an in-use configuration of the seal in which, with the third part engaged with the part defining the receiving formation for the shaft of the third part, a portion of the shaft of the first part is received in the passage defined through the shaft of the third part and the region of the shaft of the first part defining its engagement means projects from the third part and is received within and irreleasibly engaged by the receiving formation defined for it by the second part.