The Agilent N3301A is a half-rack width mainframe with 2-slots that accepts combinations of N330x user-installable load modules (150 W to 600 W) for easy system configuration and future reconfiguration. The N3301A holds up to two N3302A, N3303A, N3304A, and N3307A load modules, or one N3305A and N3306A load modules, allowing up to 600 watts of total maximum power.