A hex vital (normally often known as an Allen important) is needed to suit these fasteners. Conforming to ISO 4762 or DIN 912, the Speak to surfaces of the screw or bolt are protected from exterior injury. This variant is provided completely threaded in spite of length of screw. Picture: https://stainlesssteelbandingsupp44219.blogsvirals.com/29967937/5-simple-statements-about-masonry-screws-explained