The present invention relates to a device for monitoring the condition of a person, which comprises: (a) a casing (b) electronic circuitry and (c) at least one secure attachment mechanism, each comprising a first member which is capable of moving in a forward direction up to a locking state, at which it is interlocked by at least one second member, so that said first member cannot be moved backward by applying a first backward force, unless said interlock is unlocked, by applying at least one second force, independent of said first force. Preferably, said first member is a spike having at least one recess, wherein at said locking state said second member is introduced into said recess, thereby preventing said spike from moving backward.
