KALA U-BASS RMBL-FS RUMBLER MAHOGANY ACOUSTIC-ELECTRIC - Mahogany Top, Back and Sides - Black Binding - Mahogany Neck - Rosewood Fingerboard - Standard Headstock - Graph Tech TUSQ® Nut - Composite Saddle - Custom Black Die Cast Tuners - Adjustable Truss Rod - With Padded Gig Bag - The Kala Rumbler is one of the most affordable instruments in our distinctive line of award-winning, portable U•BASS®. Heavy on low end and light on the pocketbook, the Rumbler was upgraded to include the Fishman U•BASS® EQ with built-in tuner.