The SR Portamento features 5-piece Maple/ Bubinga through-neck for increased sustain and superior tone. Extended range 30 fret Panga Panga fingerboard with side line markings and dots. Adding another voice to the bass it has a Aero Silk Piezo Bridge System as well as dual Bartolini soapbar pickups and active 2 band preamp. On the back of the bass you are able to adjust the piezo volume of each string for the perfect balance. The EQ section incorporates the controls of the Bartolini pickups with the AeroSilk Piezo system. Controls include a Master volume, balance and bass & treble controls for the Bartolini MK-1 pickups and a Master volume and a tone control for the Piezo system.