DUB-507 Standard Ball Wrench .050 PDF Print $3.36 SKU: DUB-507 DUB-507 Standard Ball Wrench .050 Add to Wishlist Add to Compare Back to: Du-Bro Products Description This is a .050 Ball Wrench (4-40 Set Screw) from Dubro. FEATURES: Fits 4-40 set screw.