Members of the 24 Hour Fitness chain no longer need to worry about forgetting their membership cards and IDs when they go to the gym: All they need to bring are their fingers.
The San Ramon-based company is now using fingerprint scanners at its 60 San Francisco Bay area locations to verify members' identities. It also has started offering so-called "Cardless Check-In" this month at some gyms in other states.
To enter the gym, 24 Hour Fitness members need to punch in a 10-digit code and have an index finger scanned by a device that compares the fingerprint to one on file.
Company officials say the voluntary program allows members to show up without ID, prevents nonmembers from sneaking in, and saves the cost of making and mailing club cards.
"We're always looking for ways to make it easier for people to use our clubs," said Dan Benning, president of the company's Northern Division.
The scanners underscore the growing use of biometric technology, which uses unique physical features such as hands, eyes and faces to identify people.
The technology's increased accuracy and affordability has allowed it to move beyond police and military applications, with backers calling it a potential solution to identity theft.
Biometric devices are now used by companies to have employees clock in and out, by schools to restrict access to subsidized lunches and by Walt Disney World to identify pass-holders.
Privacy experts say consumers should be certain that biometric scans are stored securely and not used for any other purpose.
"Technology is advancing at a furious rate," said attorney Michael Risher of the American Civil Liberties Union of Northern California. "Stuff that seems innocuous right now may end up as part of a bigger record and used in ways we cannot even fathom."