Here's what Fender say about the Rumble 25 V3:

The all-new Rumble Series is a mighty leap forward in the evolution of portable bass amps.

With its beefier power amp and larger, ported speaker enclosure, the Rumble 25 pumps greater volume and deeper bass response. In addition to standard volume and EQ controls, the Rumble 25 adds a newly-developed overdrive circuit and switchable Contour control, delivering gritty bite and slap-worthy punch at the mere push of a button.

FEATURES
25 watts
8" Fender Special Design speaker
Top-mount control panel with ivory "soft touch radio" control knobs
Compact and lightweight (21 pounds) ported enclosure with removable grille
Switchable overdrive circuit
Mid-scoop contour switch
1/8" auxiliary input, 1/4" headphone output