This trial is a prospective, multicenter, single-arm Objective Performance Criteria controlled confirmatory study. It is for evaluating safety and effectiveness of the WEB Aneurysm Embolization System when treating wide neck bifurcation aneurysms (WNBN).The study's primary endpoints include a primary effectiveness endpoint and a primary safety endpoint. The study device must meet both endpoints. The primary effectiveness endpoint is adjudicated by an independent third party core lab.