3M Secure Click Head Harness is a replacement part for use with the 3M Secure Click Full Facepiece Reusable Respirator, FF-800 series. Replacement head harness assemblies are available for 3M Reusable Respirators and can be fitted by a trained user or a service centre, if the original head harness becomes lost or damaged. 7100283489 - 00638060433645