From a T3 article relating to the Mate 20 Pro and the underwater feature!
The Huawei Mate 20 Pro
hasn't been out long and already it's getting an upgrade that gives owners even more bang for their buck – specifically from that triple lens camera
The Huawei Mate 20 Pro comes with a new type of triple lens camera, ditching the monochrome sensor of the P20 Pro
for a wide angle option. This allows it to capture even more in the frame. Ideal for underwater photography.
Now a new diving case
has been revealed that allows the phone to go deep diving so that mode can be taken advantage of. Rather than tapping the screen, where sensitivity is compromised underwater, the camera works using the volume rocker.
On its own the phone is limited to IP68 water-proofing meaning it can be taken to a depth of 1.5 metres for up to 30 minutes. The new case lets you go deeper for longer.