Hillman 1149 Type"U" Speed Nut 1/4-20 in. 12-Pack
These speed nuts are made of stamped spring steel and are meant for spaces with minimal clearance. The design is for a quick application and removal making the nuts reusable. They act as both a lock washer and nut so can generally eliminate the need for lock washers and can be used with either sheet metal or machine screws.