This is the Factory Team 5.5mm Nut Driver Bit from Associated.

FEATURES: Fits 1/4" driver handle Steel construction

INCLUDES: 5.5mm Nut Driver Bit

REQUIRES: Installing in handle

SPECS: Length: 2.9" (75.5mm) Nut Driver Size: 5.5mm  

BOX DIMENSIONS: 3.00" W. X .25" H. X 3.25" L. BOX WEIGHT: .03 LBS.