Check the listing for details. Mapex Saturn Evolution Workhorse Birch 5-Piece Shell Pack 22" Bass Azure Burst. Condition: New. Listed at 3991.79 USD. The revolutionary Mapex Halo Mount is a lateral, unique "under lug-line" suspension system that unlocks the freedom of full resonance and allows the drum to sing with an open, pure tone. The Adjustment Knob acts as a built-in Equalizer that can slightly dampen the resonance of the shell, producing a tighter and quicker decay. Whether you like to go dry in a jazz gig, or sound huge in a packed arena, the Saturn Evolution has the whole package for you. First introduced as a special edition in 2012, the Birch/Walnut hybrid shell has made its return to the Saturn Evolution line with Design Lab features. The new shell formula perfectly combines the sonic characteristics of walnut with articulate punch of birch, delivering a Dark, Punchy, Dry sound.