This is a .050 Ball Wrench (4-40 Set Screw) from Dubro.

Features

Fits 4-40 set screw.
The perfect tool for getting at those hard to reach places.
Ball wrenches make it possible to turn socket head screws or bolts
from any angle.
Transparent Yellow plastic handle.

Includes

One .050 Ball Wrench (4-40 Set Screw).

Specifications

Length: 4-3/4" (12.1cm)