Apple is reportedly developing a successor to the iPhone X that will be larger and could even include the ability to use two SIM cards at the same time, according to Bloomberg.

Dual-SIM phones allow people to use their phones in different countries without having to swap out SIM cards. It’s a key feature for business travellers, who can roam and keep their current SIM cards in their phone at the same time.

But the feature isn’t just for people who travel to multiple countries. Dual-SIM phones are common in China, India, and parts of Africa, where people use them to take advantage of different rate plans between carriers. Chinese smartphone maker Transsion even released a phone with four SIM card slots for customers with multiple accounts.

Dual-SIM phones have actually been around for a while, but larger manufacturers only started offering them in the last five years. Samsung, LG, Huawei and OnePlus all offer dual-SIM models, but they can be hard to purchase in the US. There’s actually a dual-SIM version of the Samsung Galaxy S8 on the market, but it’s not officially on sale in the US.

If Apple does indeed offer a dual-SIM iPhone, it comes at a time when the company seemed to be moving away from SIM cards. The iPad and Apple Watch now use eSIM instead, which are much smaller and permanently attached to the device -- but they can hop between carriers, removing the need to swap cards in and out.