3M™ Versaflo™ TR-973 air flow indicator may be used to indicate air flow levels of the TR-600 and TR-800 series papers when used with tight fitting face pieces. The TR-973 is designed to enable testing at various elevations and temperatures within the operational range of the PAPR system. 3M™ Versaflo™ TR-973 air flow indicator may be used to indicate air flow levels of the TR-600 and TR-800 series papers when used with tight fitting face pieces. The TR-973 is designed to enable testing at various elevations and temperatures within the operational range of the PAPR system. The TR-973 is designed to used with the TR-600 blower. Versaflo™ 7100167216, For Use With: 3M™ Versaflo™ TR-600 PAPRs