The Doctor's handcuffs

The Doctor carried two sets of handcuffs in her coat pockets during her thirteenth incarnation. When she and Yasmin Khan were captured by the lupari Karvanista, the Doctor tricked him into imprisoning her and Yaz using these handcuffs. What she did not tell the lupar was that the handcuffs were voice activated, meaning the Doctor could free herself and her companion whenever she wanted. After Karvanista leaves the two handcuffed and footlocked on an acidic planet about to be consumed by a dying star, the Doctor quickly escaped alongside Yaz to the TARDIS. However, the cuffs took a while to respond to the voice command, due to the Doctor programming them with a Scottish accent. After a long escapade across the doomed world, the Doctor and Yaz finally reached the TARDIS, where the Doctor finally managed to activate the voice command, albeit by sheer accident. (TV: The Halloween Apocalypse)