SIM trays aren't ordinarily exciting, but this tray happens to support a new memory card format called nano memory (NM).

The new NM cards are nano-SIM sized expandable memory (45% smaller than a normal SD card) and can offer a maximum read speed of 95 MB/s.

Huawei makes the NM cards themselves, eliminating potential phone slowdown due to low-quality SD cards.

The smaller format also allows this SIM/NM tray to be smaller than a traditional dual-card tray.