The PRX 150-Pro2 is solidly built in a black anodized-aluminum case with a spring-loaded side handle. It's a passive attenuator so there's no AC power.
I used the Aracom with two amps a Ampeg v4 with a Marshall Cab and a Combo. The Ampeg/Marshall is interesting because the Ampeg is 2/4/8 ohm and the Cab is 16ohm. The Aracom has the ability to mix and match ohms so it's great for my setup. The attenuation sounds great, I have to admit with the power the Ampeg puts out at full volume even at the most attenuated setting it's still too loud for what I would qualify as bedroom or apartment use. However the shear volume change is still pretty outstanding.
The combo amp is an 8ohm amp with an 8ohm speaker, luckily the speaker was already using a 1/4 jack so I just had to unplug it and put the Aracom in between the two. With this amp the attenuation can take it all the way down to practically zero volume.
In both setups the sound is really nice, of course there is a slight change in tone I don't think there couldn't be with a change in the signal like this, but it is very very minor. Part of the change is due to the speaker not being pushed as hard but I think there is a slight change due to the processing regardless.
You can also bypass the Aracom completely and play at normal volume with the flick of a switch. Another feature is the line out option, when used with attenuation there's no need to attach a speaker to the signal chain.