Many older Kirby vacuums can be found in the secondary market. Used vacuum cleaner stores generally have good deals on Kirby vacuums, and the product's quality means that you should not hesitate to buy used. Kirby bags and parts are also widely available. Great deals on used Kirby vacuums and parts can be found on eBay, too.

Kirby's signature product is the Sentria System vacuum cleaner. It has a variable-speed motor which enables it to operate in twelve distinct modes. Made of die cast aluminum, not plastic, it easily converts to a deep-cleaning upright, a carpet shampoo system, a canister Vacuum, a floor buffer, and more.

The current new Kirby vacuums product line, brand named Sentria, have a powerful airflow and HEPA 11 filtration system. This filter removes 99.97 percent of all particles larger than 0.03 microns, including dust mite feces that contribute to asthma and allergic reactions.

Here are some of the features Kirby vacuums offer:

• on-demand powered drive head; Called TechDrive power assist, it allows the Kirby vacuums to be easily pushed ahead with just one finger.
• a foot-activated control allows adjustment of the cleaning height for carpets, low-pile rugs, or bare floors. Why this is not an automated feature remains a mystery.
• LED headlights that light up the darkest corners.

Features of various products include:

• The quick-drying carpet shampoo mode provides professional results at a fraction of the cost, using off-the-shelf carpet shampooing liquids.
• The portable canister mode allows easy vacuuming of bedding, curtains, upholstery, and other hard-to-reach places.

As mentioned above, used Kirby vacuums are still good investments. The Kirby Heritage II is one "obsolete" model, made in the late 1980s, that still has a strong following. The Kirby "G" series is also highly rated among ePinions.com reviewers.

Kirby vacuums are made by the Kirby Company of Cleveland, Ohio. John Kirby, an inventor specializing in household conveniences, created a water-based vacuum cleaner in 1906. Deciding that getting rid of dirty water was too much trouble for consumers, Kirby invented a vacuum cleaner that pushed dirty air into a cloth bag, where the dirty was filtered out.

Kirby continued developing his vacuum cleaner through World War I. In 1925, he released the Vacuette Electric, the forerunner of modern multi-attachment vacuum cleaners.

Also in the mid-1920s, Kirby decided that his versatile convertible vacuum cleaner needed to be demonstrated in consumers' homes. He began the famous tradition of door-to-door vacuum cleaner sellers who made Kirby vacuums so successful and literally a household word.

A number of consumer report Web sites bear testimonials from consumers that Kirby vacuums are sold by rather pushy doorbell ringers. Complaints about Kirby sales reps range from refusing to leave when asked to breaking a consumer's current vacuum cleaner during a "demonstration" of the Kirby. Sales reps have also been accused of preying upon the elderly, humiliating potential customers, lying about free financing, and not honoring the company's three-day return guarantee.

An excellent product, the Kirby vacuum may be overpriced for those who are used to throw-away vacuum cleaners. But if you want a versatile vacuum that will last 40 years or more, a Kirby vacuum is worth a look.