A.R.M.S. # 40 Stand Alone Flip-Up Rear Sight. This is an older version, approximately two-years old, with the Aperture Windage Knob the rounded type instead of the newer beveled type. Excellent condition as this item was mounted on a safe-queen.
Current retail price is: $95.95; I will sell for $65 (OBO) plus shipping.
Pictures are available upon request.