Truglo TFX Handgun Sights For S&W J-Frame Revolvers With Front Sight Post. I had this on a 640 S&W for a couple years. Kep the sight because the new owner didn’t want the fiber optic night sight. Pick it up from me at a nice discount. I also made a punch out of a small brass mail to punch out the very small pin. Worked like a charm for me.