Ultra thin design will fit under any grinding shield or welding helmet Will not obstruct field of vision Holder has spacers that create a space between the filter material and the holder This allows the user to access the entire filter material increasing filter life while reducing breathing resistance and increasing productivity Allows the user to replace the filter when required Economical solution and alternative to disposable respirators 'Saf-Twist' design quickly attaches the cartridge to any Dentec Safety half-mask or full face air-purifying respirator facepiece NxMD filter cover protects the filter from the environment and prevents the user from contacting the filter which may contain a virus