Here's what Orange say about the Micro Terror Guitar Amplifier Head - 20w:

TINY AMP, ENORMOUS TONE
The Micro Terror is a global phenomenon. Taking its inspiration from the original Tiny Terror, this miniature monster couples a valve preamp to a solid state output section for enormous tones that make a mockery of its pint-sized frame.

Weighing in at under 1 kilo, the Micro Terror is arguably the most portable amp head on the market. When paired with its matching PPC108 cabinet, the Micro Terror’s Aux Input and Headphone output make it a perfect practice partner, small enough for even the most cluttered sideboard.

However, don’t be fooled by its miniature footprint because size is the only thing that is small about this amp. With a high tensile steel casing, the Micro Terror is built to the same high standards as the rest of the Terror family and features a single ECC83 (12AX7) preamp valve, coupled to a solid state power amp. The depth of sound (and volume) that this little thing pushes out is truly staggering, with Orange growl and bite in abundance. What’s more, the Micro Terror can be used with any 8-16 Ohm speaker cabinet.

THE MOST COMPACT AND PORTABLE TERROR AMP
Inspired by the Tiny Terror, our game-changing ‘lunchbox’ amplifier, the diminutive Micro Terror is the original micro amp.

SINGLE ECC83 (12AX7) PREAMP VALVE
Brings big tones into a small package. Huge harmonics and dynamics from a really tiny amp.

20 WATTS RMS SOLID STATE OUTPUT
More than capable of powering our largest speaker cabinet, the PPC412 the Micro Terror is compatible with any cab with an impedance of 8 Ohms or greater.

AUXILIARY INPUT
A 3.5mm Aux. jack means you can plug in any phone or audio player and jam along, making this a great amplifier to practise with.