3M™ Versaflo™ Filter Cover, TR-6800FC Filter cover for use with the TR-6820E filter. 3M recommends the use of the filter cover in order to help protect the TR-6820E from physical damage. It is also used to hold the TR-6600 Prefilter or TR-662 Spark Arrestor in place. The TR-6800FC should be replaced when damaged. The filter cover may be cleaned and reused. Filter cover for use with the TR-6820E filter Filter cover helps protect the Filters from physical damage Enables use of prefilters and/or spark arrestors Enables turbo to be worn through decontamination showers