Details Used to hold 3M™ Filters 1744 and 1744C. For use with 3M™ HF-50 Single-Cartridge Facepiece Reusable Respirator Series. Compact design increases vision and safety. Lightweight body and cradle head harness increase comfort. Used to hold 3M™ Particulate Filters 1744 and 1744C in place on top of 3M™ Respirators HF-50 Series. 3M™ 1700 Filter Holder is a containment filter used with 3M™ HF-50 respirators to secure particulate filters and protect the user.