UNC 3/4" Socket Screw Countersunk High Tensile 10.9 DIN7991 UNC 3/4" (10 T.P.I.), Coarse Pitch, High Tensile (Grade 'S'/ 10.9), Self Colour. Countersunk Head, Allen/ Hexagon Socket Screw/ Bolts A countersunk head is designed so that the head sits flush on the fastened material's surface.
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