Designed to be used with 3M SecureFit 500 Series safety glasses, the 3M SecureFit Replacement Foam Gasket SF500-FOAM helps limit eye exposure to dirt and debris while providing added comfort and cushioning. Small vents in the gasket help limit fogging.Designed to be used with 3M SecureFit 500 Series safety glasses, the 3M SecureFit Replacement Foam Gasket SF500-FOAM helps limit eye exposure to dirt and debris while providing added comfort and cushioning. Small vents in the gasket help limit fogging.