(From the ZVex website)

The Super Hard On, or ‘SHO’ as we fondly refer to it, is an ultra-transparent boost that goes from unity gain to a whooping 60 times the original size (watch out!), while adding a delightful high-end clarity with its 5 million ohm input impedance.

Pedal Dimensions (LxWxH):  4.70" x 2.38" x 1.82"

Instructions (PDF)