Flat-Top fasteners combine under-cut hex washer heads with EPDM cut-tubular sealing washers. They are a superior and cost-effective alternative to standard fasteners with metal back washers.
One-piece design eliminates damage to painted washer surface and eliminates dissimilar metal washer materials
Flat on top stabilizes socket during installation
Higher hex provides positive socket engagement
Special undercut entraps sealing washer, even when driven at extreme angles
Assembled with an EPDM Cut Tubular Washer
 
Designed for use where self-tapping / self-drilling applications are needed.