disposed about a mandrel the length of the outer tube 4 extending from the outer mid shaft taper 7 to the distal end 3 is about 30 40 cm with an inside diameter of about 0 034 0 038 inch an outside diameter of about 0 040 0 044 inch and a wall thickness of about 0 003 inch the stiffening tube 6 as seen in fig1 is coaxially positioned between the inner tube 5 and the outer tube 4 and is preferably made of polycarbonate which is relatively stiffer than polyethylene the stifferting tube may be made of any suitable polymer with the appropriate rigidity such as polyimide the stiffening tube extends from the proximal portion of the device 2 to the outer mid shaft taper 7 for a length of about 95 100 cm and is dimensioned to slide within the necked outer shaft the dimensions of the stiffening tube 6 are an inside diameter of 0 034 038 inch an outside diameter of about 0 040 0 044 inch and a wall thickness of about 0 003 inch the dimensions of the inner tube 5 the outer tube 4 and the stiffening tube 6 may vary depending on the.