This portable subway strap won't guard you against trips and spills on the train. Rather, it keeps you safe against accusations.

Groping hands on the Tokyo underground has become something of a famous phenomenon of late, but it's a real problem. So much so that women can opt to ride in a section of the train just for them — no boys allowed. But the fear these groping incidents inspire is now double-sided. The women are rightfully afraid of lewd hands on the subway, and the men worry of being falsely accused.

Think the idea sounds too simple to work? Fear is a powerful selling tool and, at only $5 a pop, these portable subway straps have been flying off the shelves. The straps were featured on the cover of Japanese magazine Tsuhan Seikatsu, and quickly sold out afterward.

Via Pink Tentacle