The TruGlo Brite-Site Tritium Sight Set for Glock (High) has a snag-resistant design and fits standard holsters. This model sight fits Glock 20, 21, 29, 30, 31, 32 and 37. CNC-machined, steel construction provides superior durability for combat or competition. It is high quality, self-illuminating and has tritium tubes that glow bright green so you can find your sights, even in complete darkness. Surrounding white ring shows up well in daylight. Popular, three-dot system provides fast sight alignment in high stress situations.