3M Molten Metal Neck Guard NG2 GR is designed to protect against molten metal splash, radiant heat and flame hazards. It attaches to 3M and other hard hats using hook and loop fasteners on the inside of the shell. Internal attachments allow for use with or without earmuffs attached to the hard hat.3M Molten Metal Neck Guard, NG2 GR, is designed to protect against molten metal splash, radiant heat and flame hazards. It attaches to 3M and other hard hats using hook and loop fasteners on the inside of the shell. The NC2 GR uses a streamlined design to provide protection against small splashes and spatter. Internal attachments allow for use with or without earmuffs attached to the hard hat.