Very nice! It was the first iteration of the Guardian label to carry the Lux designator--previous ones were simply labeled "Guardian" or "Guardian Encore". When the Aerus brand was fully implemented in 2004, the numeric labels were dropped; so the "Guardian" moniker was brought back for the direct sales model (for several years it was only used for the indirect sales line). Your models are: for the main unit, C154E; and for the power nozzle, N137S. They were manufactured by Eureka--either in Texas or Mexico.
The styling was also used with the Renaissance, Epic 8000, & Lux 9000 labels; although the Guardians were the only ones to have the HEPA filter. Altogether the series had a dozen tank models and about 10 pn models--both for direct and indirect sales--in its 15-year run, from 1994-2009.
If you need the instruction booklet go to aerushome.com and select the "service" link.
Happy Luxing!