Abstract: An adaptable seal for use in a trocar or trocar converter is provided. The seal comprises a membrane having a radially proximal edge and a radially distal edge, at least one lobe terminating at said band, and preferably a band located at the radially proximal edge. The seal is thus able to adaptably receive surgical instruments of various diameters. The seal may further comprise means for forming a fluid-tight seal between the upper surface and the lower surface of the seal when an elongated object is received through an aperture in the seal, and at least one trough or wall. A seal according to the present invention is able to accommodate radial movement of the surgical instrument within the cannula of a trocar. A trocar and a trocar converter also fall within the purview of the present invention.