Abstract: A charging base includes: a base seat installed on a floor surface; a columnar tower part provided on the base seat; a first support provided on the tower part and capable of supporting a vertical first electric vacuum cleaner; and a second support provided on the tower part and capable of supporting a vertical second electric vacuum cleaner. An electric vacuum cleaner system includes the charging base configured as described above, the vertical first electric vacuum cleaner, and the vertical second electric vacuum cleaner.

Abstract: Ferritic heat-resisting cast steel, which intends to highten the applicability for use of the exhaust manifold of a vehicle engine without losing oxidation resistance, machinability and structural stability, containing, on a weight basis, 0.05 to 0.5% C, 1.0 to 2.0% Si, less than 0.6% Mn, less than 0.04% P, less than 0.04% S, less than 0.5% Ni, 10 to 20% Cr, 0.1 to 1.0% V, 0.5 to 1.0% Nb, 0.08 to 0.50% Mo, less than 0.01% W and 0.01 to 0.2% Ce, the balance of its composition being iron. Alternatively, it may contain 0.1 to 1.5% Mn and 0.01 to 0.2% S, and may further contain 0.01 to 0.2% Te and/or 0.01 to 0.3% Al. Further, it may contain 0.1 to 5.0% Co and/or 0.1 to 5.0% Ti. The cast steel is annealed at a temperature of 850.degree. C. to 1000.degree. C. for one to five hours.