2. If motor driven brush type [Footnote: Her selection may include either motor driven brush type or air type machine, since properly designed, either will care for all kinds of soil, including thread and lint.], there must be correct relation between air suction power and brush sweeping action.
3. As light a construction as is consistent with quality.
4. If air type, a narrow floor nozzle so designed as to clean by small amount of air at high velocity.
5. If air and brush (geared to wheels) type, a broader nozzle with inset brush is permissible provided care is exercised in design to prevent air leakage. This type cleans by a larger volume of air with correspondingly lower velocity.
6. Durable construction, either aluminum or steel casings, an assembly that secures tight joints and seams that won't leak air.
7. Easy operation—weight of appliance not so important if weight is easily handled.
8. Convenient switch; handle designed long enough for comfortable operation at woman's height.
9. Bag, double seamed; strong, tight connections; easily emptied; durable material, preferably of cotton flannel type.
10. Winding posts for cord to be strong and conveniently placed.
11. Convenience in connecting attachments.