Tridonic pc 2x58 t8 pro sl the tridonic pc 2x58 t8 pro sl is a non dimmable high frequency ballast to run 2 x 58 watt 5ft t8 fluorescent tubes tridonic article number 22185218 tridonic pc 2x58 t8 pro sl ballasts have an average life of 50 000 hours product no 22185218 l x w x h 280 x 30 x 28 mm