1. A balloon catheter for use with an endoscope, comprising: a flexible shaft having a proximal end and a distal end; the shaft defining an inflation lumen; a balloon defining an interior and being made of translucent balloon material which is substantially inelastic; the balloon having an inflatable portion extending between a proximal and distal balloon portion, each proximal and distal balloon portion being affixed to the catheter shaft; the balloon having at least one visual marker; wherein the balloon is affixed to the catheter shaft near its distal end; and the inflatable portion includes a cylindrical working portion arranged between a proximal and distal tapering portion; the balloon in an initial configuration being deflated pleated and wrapped around the catheter shaft; wherein visual markers are positioned at a longitudinal center of the balloon and at proximal and distal ends of the cylindrical working portion of the balloon; and wherein the central visual marker is thinner the markers at the proximal and distal ends of the cylindrical working portion; a hub affixed to the proximal end of the shaft and defining at least an inflation port; such that the inflation lumen communicates between the inflation port and the balloon; wherein the visible marker is visible with an endoscope.