GLOCK night sights are equipped with contrasting tritium inserts, enabling simple, accurate and quick target alignment in all light conditions. Product Specifications Type: Night-sight Position: Front (Fits all models) Position: Rear Size: 6.5mm Models: Fits all models except G42 and G43. Standard height on G17, G19, G22, G23, G26, G27, G33, G34, G35, G37, G38, G39 (Including Gen4). Material: Steel