Professional manufacturer for segment bolts and nuts production, main applied on heavy machinery on sprockets assembly and small segments repair works. Generally, bolts' design as actual application with hexagonal and half-moon head, whilst, the design of unthread rod diameter is bigger than thread rod diameter can guarantee the best strength to be hold on working well in field. Whilst, nuts' design is also thicker than common. Whilst accept to mark the logo as yours conditions on acceptable order quantity. http://railsteels.com/rail_bolt_18.html