3M™ Versaflo™ Pre-filter, TR-6600 Pre-filter can extend the service life of the particulate element of TR-600 series filters by capturing large particles that may otherwise clog the filter. Frequent pre-filter changeout may help optimise system performance. Pre-filter can extend the service life of the main filter by capturing large particles that may otherwise clog Frequent pre-filter changeout may help optimise system performance May reduce operating costs by extending the life of TR-600 series filters Pre-filter TR-6600 may be used with TR-662 spark arrestor The TR-6600 is maintenance free and should be discarded when clogged or damaged