4FF stands for 4th Form Factor. A SIM card that is simply physically smaller than a traditional (2FF) SIM card or Micro-SIM (3FF) card. See: SIM The electric contacts and circuitry of a Nano-SIM ...

That’s dependant on not only which size SIM card you have, but model of iPhone you have too, as older iPhones use standard SIMs while more recent iPhones opt for the Micro- or Nano-SIM.

[RoyTecTips] shows us an ingenious hack which turns a single-SIM-slot phone into a fully functioning dual-SIM phone. All that’s needed for this hack is a heat-gun, solvent, micro SD card, nano ...

What if you want to take your iPhone 5 nano-SIM and go back to a micro-SIM phone? We already know that you can fit a nano-SIM into a micro slot, basically destroying your phone.

[RoyTecTips] shows us an ingenious hack which turns a single-SIM-slot phone into a fully functioning dual-SIM phone. All that’s needed for this hack is a heat-gun, solvent, micro SD card, nano ...

One of the originators of the SIM standard has designed a new “nano-SIM” that’s considerably smaller than the micro-SIM it hopes to replace.

Nano-SIM war: here’s what Apple and Nokia want to put in your next phone The Verge has obtained detailed information on the so-called “nano-SIM” proposals from Apple, Nokia, and RIM.

Want to squeeze your current SIM card into your brand new iPhone 5? Check out our DIY guide to find out how.

The new design is 40% smaller than the current micro-SIM standard. Today's SIM card designs take up a significant amount of space inside a mobile device.