A low profile protective helmet having an outer shell and an interior surface that is immediately adjacent the top of the wearer's head while the helmet is being worn. The interior surface includes a plurality of fasteners that are connectable to a prior art suspension liner. Each of the fasteners is disposed between first and second rib members. Each rib member is a raised ridge in the interior surface that restricts the side-to-side movement of the suspension liner's integral head straps by the retaining action of the rib members as the integral head straps are attached to each fastener.