This is a Metric Precision Tool Screwdriver: #0 Phillips.

Designed for use with Micro radio controlled vehicles that have Metric-
type hardware.
Precision drivers have hardened chrome vanadium shafts for extensive
torquing. All drivers (except the nut drivers) have hardened tips.
Rubberized handles are tapered for rapid turning ease. Textured
finger grips offer comfort and a secure, slip-free hold. Rotating
caps increase fingertip control.