Manual sample injectors have two positions, 'Load' and 'Inject'. The 'Load' position allows sample loading into the sample loop or sample chamber. A syringe is commonly used to load sample into the sample injector. After loading, manual rotation of the sample injector's handle to the 'Inject' position allows the flushing of loaded sample onto a column.

* MBB™ (Make-Before-Break): Models incorporating Rheodyne's patented MBB architecture design provide uninterrupted flow when switching between 'Load' and 'Inject' positions.