A device in the form of a small attachment intended to be fitted to the working channel (including biopsy port) of an endoscope to enable access for, and/or exchange of, an endoscopic device while minimizing leakage of liquids and gasses during an endoscopic procedure. Also referred to as a seal, it may be Luer formatted and include features to allow for simultaneous irrigation/biopsy or suction via the working channel. This is a reusable device.