"C/O TWO CELL ASSEMBLY,OPTICAL INSTRUMENT. DIMENSIONS,2.682 IN. MAX O/A LG,0.812 IN. MAX O/A DIA. CELLS SECURED TO EACH OTHER BY MATING THREADS. ONE SINGLE LENS EACH CELL WITH THREADED RING SECURING METHOD. CELL MATERIAL ALUMINUM ALLOY,ANODIZED-BLACK SURFACE TREATMENT."