Which device allows entry into donor units without affecting the expiration date of the product?

The sterile docking device is specifically designed to allow for the connection and transfer of blood components without compromising the integrity of the donor unit or affecting the expiration date of the product. It provides a sterile interface for transferring components while maintaining the sterility of both the blood product and the recipient system. This is crucial in blood banking, as contamination of blood products can lead to serious complications, including infections and the potential rejection of transfusions. By using a sterile docking device, blood banks can safely manage the product while ensuring that the expiration date remains valid, as there is no disruption in the closed system that typically governs blood storage.

The other options, while relevant to blood banking processes, do not directly address the requirement of maintaining the expiration date through a sterile entry method into donor units. Therefore, the sterile docking device is essential for preserving the quality and safety of blood products in a way that directly meets the needs outlined in the question.