Socket Flat Head sealing screws have a socket recess and is cone shaped for use in countersunk holes the flat top fits flush with the mated surface. ZAGO’s line of self-sealing screws, bolts, and nuts offers you unsurpassable fastening and sealing power. Each of our fasteners is equipped with a unique, malleable and strong captive O-ring. This device delivers extraordinary results. The O-ring, which fits tightly and precisely in the groove under the screw/bolt/rivet head, acts as a total deterrent against external/internal contamination from air, water, gas and other materials. As a result, your screws and bolts will perform like never before, granting your most sensitive equipment unbeatable protection with 360 degrees of sealant while achieving metal-to-metal contact.