There are now four physical sizes for SIM Card. In the TS standard the physical card is referred to by its correct technical name an UICC (universal integrated circuit card), the UICC thus cover the transmission technologies of for GSM and 3G. Interestingly, although TS.102221 makes no reference to SIM but USIM, the generic use if the term SIM Card is still applied
1FF: ID-1 uicc size (the size of a credit card)
2FF: Plug-in uicc (the size of a postage stamp)
3FF: Mini-uicc (the size of a finger-nail)
4FF: XXXX-uicc (12.3mm wide by 8.8mm high, and 0.67mm thick) A titled suggested for this new uicc size is nano-size. It is my suggestion that a fair representation of its size is **eye contact lense size, which might be of useful assistance to a Court or Jury.
Image courtesy of http://en.wikipedia.org/wiki/Contact_lens
The diameter of a contact is the distance across the lens in millimeters. Average eye measurement for diameter yields a size between 12 and 14 millimeters. Diameter is important for proper fit of the lens. If the lens is too small or too big, it can cause irritation or damage to the eye.
Quick reference source: http://www.ehow.com/facts_6163786_average-eye-measurement-contact-lenses_.html
Currently TS10221 displays the characteristics for plug-in uicc and mini-uicc as:
Regarding ID-1 uicc the ETSI TS records:
4.1 ID-1 UICC
The physical characteristics of the ID-1 UICC shall conform to ISO/IEC 7816-1  and ISO/IEC 7816-2 .
The terminal shall accept embossed ID-1 UICCs. The embossing shall be in accordance with ISO/IEC 7811-1  and ISO/IEC 7811-3 [i.1]. The contacts of the ID-1 UICC shall be located on the front (embossed face, see ISO/IEC 7810 ) of the card.
Discussion Updated 08-06-2012
ETSI release details of new 4FF UICC