.400″ Short body standard slotted self-ejecting fastener kits have a grip range of .098″ to .133″. These spring loaded buttons guarantee a quick release. The spring holds the button captive so that it can’t be dropped underneath the car or into some hard-to-get-at area of the chassis.They’re a necessity for quick pit work in both drag racing, and oval track. Each kit contains (10) fasteners and (10) 1″ springs. Use 085 71430 springs for replacement.