4-strings bass from Jackson X Series Signature David Ellefson Concert Bass. One of the original godfathers of thrash-metal bass, Megadeth’s David Ellefson levels audiences all around the globe with his aggressive playing style and guttural bass riffs. Jackson and the esteemed bass master joined forces to bring you a fresh take on the X Series Signature David Ellefson Concert Bass CBXM IV — ravishing in look and sound, exquisite in feel, and loaded with personal design touches straight from the man himself.