The UBASS-RMBL-FS produces the same pitches as a standard bass instrument and is tuned in traditional bass tuning: E-A-D-G. Featuring 16 frets in a 21" scale, the Rumbler UBass has an active EQ and built-in tuner to provide tone control and spot-on tuning. The rosewood fingerboard on this fretted UBass has a custom Kala inlay, as well as top and side neck-markings at the 3rd, 5th, 7th, 9th, and 12th positions to help identify the 16 fret locations.

The built-in custom die-cast tuners ensure the instrument will stay in tune, and the Graphtech black TUSQ XL nut and saddle deliver a balanced tone. The Rumbler UBass is set up with Kala's silver Rumbler strings, and includes an embroidered gig bag for transport.