The TRUGLO universal shotgun vent rib red dot mount allows you to mount a reflex red dot sight to your shotgun without the need for a picatinny rail. As long as your shotgun has a ventilated rib between 0.236 in. (6mm) to 0.395 in. (10mm), this mount will work. Featuring an Doctor footprint, this mount is compatible with many of the red dot sights on the market. FeaturesMounting Hardware and Tools IncludedFits Ribs 0.236" to 0.395" in Width