3M 7500 Series Respirator Strap Clip

These replace the clear injection molded parts that have a living hinged design.

Note: The opening is about 0.5mm and really bites into the 1mm thick straps. Use a lighter if the ends of your straps are frayed. I think the neck pieces fits most 3M masks, but the side pieces might be compatible only with the 7500 Series.