These older cell phones make it easier to hide
your text messages. Appropriately enough,
the phones are called the "F-Series".
From The Wall Street Journal:
Over the past few years, as many people rushed to trade in their old phones for smartphones, Japan's philanderers have remained faithful to one particular brand: Fujitsu Ltd.'s older "F-Series" phones, which feature some attractive stealth privacy features.Read more: Japan's Philanderers Stay Faithful to Their 'Infidelity Phones' , Wall Street Journal>>
The aging flip-phone—nicknamed the "uwaki keitai" or "infidelity phone"—owes its enduring popularity to customers who don't believe newer smartphones are as discreet at hiding their illicit romances.
A Japanese blogger who goes by the name Bakanabe and writes anonymously about picking up women, said he looked into buying a new device but found the privacy settings fell short of his current phone. Instead, he opted to refurbish his battered, three-year-old Fujitsu flip-phone with a new casing and a new battery.
"Women may want to check my phone for strange emails or calls when I'm not around. With Fujitsu's 'privacy mode,' they can't see that information at all," he said in an email. "The key is to give off the impression that you're not locking your phone at all."