SIM-free iPhone 6S now available in US

Apple has put on sales SIM-free iPhone 6S and 6S Plus models in the US.

As the SIM-free iPhone comes unlocked, the user is not tied to a carrier or multi-year carrier contracts, which gives users more freedom to choose between plans.

However, the main difference between SIM-free and contract-free unlocked iPhones appears to be the network bands supported.

The SIM-free iPhone 6S carries the model number A1633, while the larger iPhone 6S Plus is A1634.

Apple's site states that the model is best suited for AT&T and all the other smaller carriers like Cricket or US Cellular, due to its support for their LTE networks.

The other version available globally and the one users would get with Sprint, T-Mobile and Verizon is the A1688 for the iPhone 6S and A1687 for the iPhone 6S Plus.

This model is listed to support the LTE networks in countries such as Canada, the UK, France, Germany, Hong Kong, Japan, Singapore, and Australia.

Users in China would need the third version – A1700 for the iPhone 6S and A1699 for the iPhone 6S Plus, which supports the three big carriers of the country China Mobile, China Telecom and China Unicom.

While with the iPhone 5S and iPhone 6, Apple started rolling out SIM-free models several months after initial sales started, this time it had only been two weeks since the iPhone 6S became available.

"If you don't want a multiyear service contract, or if you prefer to use a local carrier when traveling abroad, the SIM-free iPhone is the best choice," Apple says.

The company further says that SIM-free iPhone 6s units would work on a multitude of networks including those run by AT&T, Verizon, T-Mobile and Sprint in the US International support was also offered thanks to iPhone's multi-band LTE radio.

Apple's website features a full list of supported networks. Customers can activate SIM-free iPhones on any compatible GSM or CDMA network.

SIM-free iPhones are not eligible for carrier incentives of payment plans so customers would need to pay the entire handset cost upfront.

Leading up to the launch, in China's southern boomtown of Shenzhen, over 30 unauthorised stores carrying Apple Inc's iconic white logos have been peddling pre-orders for the new iPhone, a gadget that has become a status symbol among many better-off Chinese. (See: Unauthorised iPhone stores mushroom in China ahead of 6s launch).