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

FEATURES: Hard anodized metal construction with laser etched hex size Ideal for easy access to shock mount nuts, or other hard to reach 5.5mm nuts

INCLUDES: Factory Team 5.5mm Short Nut Driver  

BOX DIMENSIONS: 1.75" W. X 1.00" H. X 3.25" L. BOX WEIGHT: .02 LBS.