Sock it Out MEB-1 4 Piece Metric Socket Head Cap Screw Extractors, Removes Screw Size M-3, M-4, M-5, M-6 Heavy duty left & right hand screw extractor. Approved by GSA and used worldwide by all branches of the U.S. government. Supplied in vinyl case. Unique tapered hex design wedges deeply into the stripped socket head to ensure a positive, non-slipping engagement.