Ultimaker Print Cores are used with the Ultimaker 3, Ultimaker 3 Extended, and Ultimaker S5 3D printers. The Print Core AA (Build Core) is used for fabrication of the actual object, whereas the Print Core BB aka the Support Core is used for creating dissolvable supports. Maximize your uptime with new, swappable Ultimaker Print Cores. Achieve extra fine detail with a swappable 0.25 mm print core AA when printing build materials including Nylon, PLA, CPE, ABS, and PP.