Sonic sunglasses

The sonic sunglasses were a device the Twelfth Doctor used to replace his sonic screwdriver after he abandoned it. They were worn as normal, black sunglasses with no visible difference to non-sonic versions. He used them to recall the TARDIS after it had been dispersed by the HADS "dispersal" function. He expressed concern that, whilst in the possession of Davros, they might have become scratched. (TV: The Witch's Familiar)

He wore them during his three week visit to Essex, 1138. He referred to them as "wearable technology". (TV: The Magician's Apprentice / The Witch's Familiar)

The Doctor used them again in the underwater base the Drum in the year 2119 to tune onto the base Wi-Fi in order for the base crew to get a look at the ghosts after they were trapped. (TV: Under the Lake)