Adjustable objective Tube diameter 25.4mmAOR15 4-16X50AO $26.6AOR16 6-24X50AOS $27.5 AOR17 3-9X42AO $23.0AOR18 3-12X40AO $20.5AOR19 4-16X40AO $22.0 AOR20 6-24X40AO $26.8 AOR21 4-12X42AOWA $25.2AOR22 3-9X42AOWA $25.2 AOR23 4-12X50AOWA $28.0