This is the prototype of the manual sonic screwdriver, with thumb-actuated trigger. The internal workings have been removed for other prototypes; as this model was considered impractical, the design feature known as the 'round things' can be clearly seen in future incarnations of the "Tardis", The Doctor's infamous TT Type 40 Mark 3 Tesselecta database
11th quotes XXL

This is a handle handle. Because your handle needs a handle for convenience.
When Worlds Collide, XXL