The ML17777 is a fixed set for use on the CZ 75 and CZ 85 pistols that have a push in front sight held by a roll pin. This is the current production design used on the CZ USA pistols. The rear sight is the #5, which is their standard height. MEPROLIGHT sights, like our other self-illuminated products & devices take maximum advantage of tritium light sources - the fail-safe, maintenance-free light sources that don?t require any external source of energy and provides up to 15 years of usable light under all weather conditions. MEPROLIGHT continues to offer the strongest guarantee in the industry for the usable light of our TRU-DOT sights..