The Sonic-FX Duo offers the same awesome sonic technology as the Sonic-FX Solo—times two! The Duo stand offers one charging peg and one storage peg. Each toothbrush is capable of over 33,000 strokes per minute, ultra-lightweight, and are each rechargeable. The intelligent timer has a 2-minute shut-off to ensure optimal brushing time and at three different speeds: Super, Normal, and Massage. Why have just one sonic powered toothbrush, when you can have a DUO?!