Megadeth’s David Ellefson used a very special 5-string Jackson Concert Bass on the tour for 1990’s thrash classic Rust In Peace. David has a lot of great Jackson models that really suit who he is as a player now, but a lot of fans have an emotional connection to that particular 5-string Concert Bass. Well good news! From Jackson:
“The poplar body features ergonomic contours that provide the perfect platform for launching a musical assault—the upper contour provides a comfortably stable anchor for pick or fingerstyle playing alike while the lower contour provides perfect balance when propped on a knee for monitor stands. The through-body quartersawn maple neck features a scarf joint and graphite reinforcement rods that protect against extreme environmental and climate changes. Built for highly technical lightspeed playing, the 12”-16” compound radius laurel fingerboard flattens out as you move up the neck for increased playing comfort and speedy articulation.
Earth-shaking EMG® P and EMG J pickups in the neck and bridge positions provide plenty of girth and cut. Dial in your thunderous bass tone with a three-way toggle switch, single volume control and two-band EQ to boost treble and bass. The Jackson HiMass™ 5-string bridge sharpens your notes’ attack for extra punch and clarity, granting enhanced sustain without significantly altering the bass’ fundamental tone.”
More info here. And you can see that original bass at the very beginning of this here video: