This is the Pocket Size Mini Hex Socket Wrench from Integy.

FEATURES: Four common hex sizes used on RC vehicles 4mm, 5mm, 5.5mm and 7mm Small size fits easily into pocket or car bag

INCLUDES: Pocket Size Mini Hex Socket Wrench

SPECS: Length: 1.9" (48mm)  

BOX DIMENSIONS: 3.00" W. X .38" H. X 3.25" L. BOX WEIGHT: .04 LBS.