Abstract: A wirelessly detectable tamper-evident seal (1) including a receptacle part (10) and a frangible part (50), the receptacle part (10) including a first receptacle (10a) and a second receptacle (10b-d) attachable to a container to seal a closure of the container and the frangible part (50) including a first portion (51) and a second portion (52) frangibly connected to each other, the first receptacle (10a) adapted to receive the first portion (51) and the second receptacle (10b-d) adapted to receive the second portion (52), the frangible part (50) including a transponder (54), the second portion (52) able to be trapped against movement in the reverse direction in the second receptacle (10b-d) to effect a tamper evident seal between the first and second receptacles (10a-d), wherein the transponder (54) includes at least two circuit interruption locations (94a, 94b) that must be connected to activate the transponder (54) and the transponder (54) is activatable by inserting the second portion (51) in the second re