Designers Ti Chang and Michael Topolovac, from San Francisco, developed the sleek non-frilly device after hearing the most common complaint from vibrator-using women was the hassle caused by bulky charging devices.

Mr Topolovac said: 'Two female friends were expressing their frustration over the products and shopping environments in the world of sex toys.

'I was struck by the profound gap between the quality experience women sought and what was available.'