US customers can now get their hands on an unlocked, SIM-free iPhone 5S through Apple.

Apple has just updated its online store, adding an unlocked, SIM-free iPhone 5S to its lineup. The smartphone starts at $649 (£400) for the 16GB model, and it goes up to $749 and $849 for the 32GB and 64GB models respectively. 

Buying an unlocked, SIM-free iPhone 5S means you will own Apple's latest handset without any carrier attachment, making it uniquely different from the unlocked T-Mobile variant that comes with a Magenta nanw3ao-SIM.

The SIM-free GSM iPhone 5S still requires data connection in the form of a GSM-compatible nano-SIM card from either AT&T or T-Mobile, though. So, while you aren't completely free from carriers, you aren't limited to just one either.

A SIM-free iPhone 5C has been available in the US since launch, while international countries - including the UK - have long had access to a fully unlocked iPhone from the iPhone 5 series.

READ: iPhone 5S review

Still, for frequent travellers in the US, the unlocked, SIM-free iPhone 5S is worth checking out. All models have a shipping estimate of around one to two weeks at the moment.