Unlike many other phones that have a hybrid slot, the F7 comes with dual 4G SIM card slot and a third slot for adding a microSD memory card (supports up to 256GB).. The good thing about this offering is that unlike Hybrid slots where you need to sacrifice the microSD card slot for a second SIM card (or vice versa). With the triple slot tray you don't have to do that.
The tray has three slots, so you can use two different SIM cards for separating business calls and private calls or domestic calls from international calls and still use a micro SD memory card slot to expand over the built-in storage of the device.
The Oppo F7 comes with either 64GB or 128GB of built-in storage space (ROM), but for some people this might not be enough, especially when you play to take many pictures and videos when traveling abroad. Now if you want to use a second SIM, with Hybrid card slots you have a problem.
I had this problem when I visited Barcelona last year. I wanted to use two SIMs, and also a microSD card because I enjoy taking lots of photos and videos when I travel. the problem was that with my dual-SIM phone I couldn't because it has a hybrid card tray, not triple card slots like the Oppo F7. So this is definitely a great advantage for those who needs it.