River Song's sonic screwdriver

River Song owned a sonic screwdriver — a modified version of the screwdriver that belonged to the Tenth Doctor — which was gifted to her by the Twelfth Doctor, as part of a way to enable his tenth incarnation to save River's consciousness after her death in the Library.

Appearance and technology
River Song's sonic screwdriver resembled a heavily modified version of the model of sonic screwdriver used by the Doctor's ninth and tenth incarnations. This screwdriver was fitted with dampers (or alternately spelled dampeners), red settings, and a neural relay data-chip. (TV:, PROSE: )

Uses
Among its functions, most of which were shared with the Doctor's screwdriver, River's screwdriver was capable of increasing the mesh densities of her expedition's suits to over 800%, (TV: ) activating and disabling the Library's gravity platforms, slowing the descent of a fall within a gravity well, fixing light bulbs and storing the consciousness of an individual held within its neural relay. (TV: )

History
The Doctor, having previously saved River Song's consciousness in his tenth incarnation, knew to add the neural relay to the screwdriver to enable his past self to save River in the first place. (TV:, PROSE: )

The Twelfth Doctor, during his last date with River in the Singing Towers of Darillium, gifted the screwdriver to her; this was the first gift the Doctor personally gave to River face-to-face, after seeing that she was using a sonic trowel, which he found "embarrassing". When the Doctor gave River the screwdriver, he scanned her with it for the neural relay under the guise of playfully demonstrating it to her. (TV: )

River told Helen Sinclair that it was better than the Doctor's. (AUDIO: The Sonomancer)

In 5150, after River sacrificed herself in the Library, the Tenth Doctor was able to use the neural relay in River's screwdriver to upload River's data-ghost into the main computer of the Library. (TV: )