4, 5, 6-string · Set-neck (deep-set)
Caesium: Multiscale-option ergonomic boutique bass hand-built in Almeria, Spain by Alejandro Ramirez (o3 Custom, since 2005); 34"-35" multiscale option; 22 or 24 Jescar EVO Gold frets; Haussel Bassbars with coil split; Gotoh Resolite tuners; ETS bridge; ultra-thin acrylic finish; Hiscox hard case included. 4/5/6-string. Often built multiscale with master-grade exotic tops (e.g. poplar burl) and multi-piece necks
| Construction | Set-neck (deep-set) |
| Strings | 4, 5, 6 |
| Body | Honduras mahogany, walnut, or swamp ash (exotic tops available) |
| Neck | Hard maple or walnut (multi-piece) |
| Neck Pickup | Haussel Bassbar |
| Bridge Pickup | Haussel Bassbar |
| Controls | Volume, balance, tone; coil-split mini-switch |
| Bridge | ETS (through-body string option) |
| Made In | Spain |