The Mossie Midnight Mount is designed to place a 1913 Picatinny based weapon light at 12 o'clock for ambidextrous use. It easily installs on most standard and "F" marked front sight bases (FSB). The host weapon is not modified, which is especially important to many law enforcement officers who may not be allowed to alter their issued weapons.NoteInstallation is simple: approach the FSB at a slight angle near the top and wrap the locking arms around the vertical post before sliding it down into position. Tighten the two included patched set screws with a 3/32" Allen wrench (not included) to level and secure the mount.Unobstructed sight picture for the following: Surefire X300, Streamlight TLR1, TLR3, Streamlight/Insight Technologies M3, Insight Procyon/WX150, NEBO 180 Lumen Weaponlight.