This is a Precision Nut Driver by DuraTrax.

Hardened Chrome Vanadium shaft & end adds strength and durability.
Rubberized handle with textured finger grip combines comfort with
a slip-free hold. Top of handle has flats on both sides so it
won't roll away when set down on a work surface.
Tapered handle allows rapid rotation.
Color coded (blue), finger pivot cap for easy identification and
precise finger-tip control.
The size is printed, in White, on the Black handle.
Comes in a clear plastic cover on a peg board header card.

One Precision Nut Driver

Socket Size: 3/8"
Shaft length: 75mm
Overall length: 175mm
Handle Top Flats: 15mm and 20mm

DuraTrax precision tool caps are color coded as follows:
COLOR CODE: Red = Precision Slot/Phillips Screwdriver
Yellow = Precision Ball Hex Driver
Blue = Precision Nut Driver
JAL 7/20/00
ir/jl
kr3/14/03