Dr. Z Z-Air Brake Guitar Amplifier Attenuator Features:

Dial's back your amp's output without sacrificing tone
Crank up into breakup, even at bedroom levels
Great for tapping into any amp's sweet spot
Fit for practice, performance, or recording
5 levels of attenuation, with Bedroom (softest) being continuously variable
Compatible with any tube amp up to 100 watts
Accepts 4-, 8-, or 16-ohm loads