The Ameriglo Ghost Ring Sights for the Glock 20, 21, 29, 30, 31, 32, 36, 40, and 41 Gen 1, 2, 3, 4 utilize an aperture style rear sight with two tritium mini-dots and a bright tritium front sight providing quick front sight acquisition by leading the eye to automatically center itself in the rear ring while focusing on the front sight. Preferred sights for shooters seeking an alternative to traditional post and notch sight design. AMERIGLO is committed to manufacturing the highest quality tritium, painted dot, fiber rod, and custom OEM iron sights for the modern hand-gunner. With the largest selection of set options for leading firearm brands, AMERIGLO brings a clear advantage to your shooting experience on and off the range. DISCLAIMER: This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.