This is a Hi-Viz Sight known as the Litewave, model SF2109.
HIVIZ(R) LiteWave(R) Rear Sight for Springfield Armory 1911 pistols. Fits all production models; does not fit GI and Mil Spec models. Includes Green" Red and Black replaceable LitePipes.
Features:
Interchangeable Litepipe rear sight
Includes green red and black LitePipes;Factory height rear sight .140 wide notch
