The vitrex 331231 powertool and mdf premium valved masks fold flat for easy and hygienic storage their breathe easy valve offers extra comfort when exerting greater physical effortbody movement the masks are ideal for working in confined positions ie when crouching or bending these fold flat masks protect lungs against fine toxic particles and are suitable for use with mdf softwoods hardwoods metals and concrete they can be used with most power tools drills saws grinders sanders routers etc en