The addition of a second syringe enables you to flush out the test article after dosing. It also provides a user-selectable "TEND" feature, which automatically flushes the catheter. This approach maintains the patency of your catheter both before and after the dose. This dual syringe approach provides maximal confidence that the exposure of the test article is restricted to the time of dosing. The washing of the dose through the catheter eliminates all possibilities of material diffusing from the catheter into the bloodstream.