Also known as pig nose or twin hole, this screw head has two spherical holes which might be opposite one another and resemble a pig’s nose. It is a safety-design and style screw to avoid tampering. You may need a special spanner screwdriver for this type of screw head. Socket-head https://typesofroofdamage27260.blogs100.com/29843629/5-essential-elements-for-kinds-of-screw-heads