Each of the em marin proximity card have a unique seiral number. It is great solution for.Access control, time attendance system which do not require very high security level. Physical Dimension£¬86x54x0.8 (+/- 0.04 )mm Weight£¬5.8g +/-0.5 Ma 0, N sli , legic mim256, jwl872, Ti256, ti2048inside picopass 2ks