Low protrusion safety fastener for ballistic helmet

A safety fastener for mounting fitting equipment such as suspension and retention systems onto a ballistic helmet. The nut portion of the fastener fits substantially within a grommet that is attached to a strap that forms part of the suspension or retention systems. The nut retains, rather than clamps, the grommet to the helmet. The grommet can be pulled off the nut. The pull-out force is less than the fastener fracture force. The configuration of the fastener allows ballistic threat energy to be absorbed by helmet deformation and delamination along with grommet pull-out to provide energy dissipation in stages which avoids the creation of secondary projectiles from the fastener itself.