This is a Hi-Viz Sight, model GL2009-R.
HIVIZ(R) Tactical Overmolded Front Sight for Glock pistols. Fits all Glock models. Features one Red" .120" diameter LitePipes.
Features:
Front sight for Glock handguns
Redesigned Glock overmold with larger .120 diameter
Interchangeable LitePipes