You are bidding on a used Bausch and Lomb 2X Auxiliary lens for a Bausch and Lomb Stereo 4 type of microscope.  The lensis used and show signs of usage and age such as corrosion on the housing, dust and minor flaws on the lens. The Auxiliary lens screws into most B&L Stereo microcopes.  The lens mounting threads are 38 mm in diameter and the largest part of the lens barrel is 44 mm. The lens is about 22 mm tall.   This item ships free to USA addresses only.