SureFire slip-on filters add versatility to your WeaponLight Filters help to preserve user&';s scotopic vision Choose F05 (red) to help you read red light-readable topographic maps, or F06 (blue) to identify fluid on dry surfaces SureFire F05 and F06 filters slip onto the bezels of select SureFire models. These filters can be flipped open and out of place when white light is needed. Both the red and blue colors can be used to preserve a user&';s scotopic vision. The F05 (red) filter improves contrast and aids in reading red-light readable topographic maps. The F06 (blue) filter assists with identifying fluid on dry surfaces (e.g. tracking blood on a hunt or finding a leaking source of fluid in an engine bay). F05 and F06 filters fit bezels 1-1.125 inches in diameter. F05 and F06 are sold separately.table.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; }