Sometimes referred to as the 2FF SIM, this is the most commonly used and largest SIM in mobile phones. It measures 1” long by .6” wide and is appropriate for phones like the Samsung Galaxy Ace, Nokia Asha, and older Blackberry phones. Plus it works with all USB modems and all pocket WiFi modems.
Also known as a 3FF SIM, the micro SIM is half the size of the standard and runs .6” long by .5” wide. Aside from the standard Apple products (iPhone 4/4s/iPad), it’s compatible with the HTC One, Sony Xperia Z, Samsung Galaxy S4, and most other 3G/4G tablets. These were developed by the European Telecommunications Standards Institute as alternatives to the larger, traditional chips and are suitable for many smaller handheld devices.
The nano SIM card is used in some of today’s most advanced mobile devices. Apple uses the nano SIM for its highly-popular iPad Mini and applies the same card to its latest generation of smartphones as well. The iPhone 5, 5c and 5s all use nano SIM card technology. It is the smallest card, approximately 40% smaller than the micro SIM which is .5” long by .5” wide and each one contains an unique serial number (ICCID) used to identify it.
Selecting the right card is just a matter of checking the dimensions of your mobile phone’s SIM slot. If you have any questions, your carrier can provide some clarity on the right option for you.