Flat tie is used on american concrete construction , X-flat tie is used with wedge bolt to fix the steel form. Nominal tie are used with taper pin and wedge to fix the aluminum formwork and sepa tie is used with the washers to fix the wood form., they are used on concrete construction. Flat tie and standard pin, standard pin and wedge , flathead pin and wedge, loop tie flat tie and wedge bolt often used together to to tighten adjoining concrete forms and securing concrete form in concrete construction.