This sight post will not fit and of the Magpul MBUS sights. It is made specifically for the Kriss Defiance Sights and will fit both the steel and polymer versions of those. For Magpul MBUS PRO and MBUS Gen 3 sight posts, we make posts specifically for each of those sights which are also available here. AR sight post models fit the MBUS Gen 2 sights.