Pack of ten standard replacement 3M™ Speedglas™ outside cover lenses (part number 526000) to suit the Speedglas™ Welding Helmet Series 9100 and the Speedglas G5-01 Heavy Duty Welding Helmets. Outside cover plates protect the outside of your 3M Speedglas 9100 or Speedglas G5-01 auto-darkening lenses from sparks and splatter. Outside protection plates are essential for the care and maintenance of your Speedglas welding helmet. It is recommended to replace outside cover lenses once to twice a week depending on use.