Here’s some info from Fender about the Rumble 15 V3
The all-new Rumble Series is a mighty leap forward in the evolution of portable bass amps.
Don’t let its diminutive stature fool you – Rumble 15 uses every last electron of its 15 watts to pump out a surprisingly rich and balanced sound. Whether it’s for an acoustic gig or backstage rehearsal, Rumble 15 delivers legendary Fender tone in a remarkably portable package.
Small and powerful, with a special magnetic mounting system that keeps the heads firmly fixed to any of the powerful and rugged new cabinets without interference from vibration, even at extreme volumes.