Posts fit Zamp 1A, 2A, 3A, 4A, and 6A head and neck restraints, Kit will include 2 mounting screws, 2 posts and 2 post base washers, One helmet-mount kit is included with the purchase of a new Z-Tech device and this kit will serve to outfit a second helmet, They are specifically designed for use with SAH helmets, It comes with backing nut / thread nut pre-installed.