The FOCUS LOCK ring is a visual element built into the front sight body that encircles the tritium insert, creating a contrasting frame around the aiming point. In defensive shooting, a fundamental principle is to focus on the front sight — not the target and not the rear sight. Under stress, the brain naturally wants to focus on the threat. The FOCUS LOCK ring gives the eye a larger, more obvious target to snap to at the front sight position, making it easier to achieve front sight focus quickly despite the stress of the situation. The result is faster, more confident sight alignment compared to a smaller bare tritium insert.

Both are TRUGLO night sights for Glock using Swiss tritium and FORTRESS FINISH, but they differ in technology and price. The TFX combines Tritium with a Fiber-Optic (TFO) element: the fiber-optic gathers ambient light to produce a bright aiming point in daylight conditions, in addition to the tritium glow at night. This makes the TFX noticeably brighter in full daylight. The Tritium Pro uses tritium only — no fiber-optic — so its daylight visibility depends entirely on the sight geometry and FOCUS LOCK ring rather than a light-gathering element. The Tritium Pro adds features the TFX does not include: the FOCUS LOCK ring for faster front sight acquisition, a U-notch rear design, and an angled rear ledge for one-hand manipulation. At $72.99 vs $109.99, the Tritium Pro is the lower-cost option when daylight fiber-optic brightness is not a priority but PRO-tier night sight features are.

Glock MOS (Modular Optic System) pistols have a milled optic footprint on the top of the slide with a removable adapter plate system for mounting slide-mounted red dot optics. On MOS slides, the sight dovetail dimensions and spacing can differ from standard Glock slides, or the front sight post area may be altered. Because of these dimensional differences, sights designed and fitted for standard Glock dovetails may not seat correctly, may not achieve proper zero, or may physically not fit on an MOS slide. TRUGLO specifies this sight set is not compatible with MOS variants. If you have a Glock MOS pistol, look for a sight set specifically listed as MOS-compatible.

Yes. The Tritium Pro is sold as a complete sight set including both the front sight and the rear sight. The front sight features the FOCUS LOCK ring with tritium insert. The rear sight features the U-notch design with tritium insert and the angled manipulation ledge. Both sights include tritium for low-light and dark conditions. No separate purchase is required to complete the sight system.

Tritium has a half-life of approximately 12.3 years. The inserts are at their brightest when new and gradually dim as the tritium decays. After roughly 12 years, brightness will be at approximately half the original level — still visible in low light but noticeably dimmer. No maintenance is required during normal service life. TRUGLO offers tritium replacement service once inserts dim below acceptable levels. Unlike fiber-optic elements, tritium inserts have no external exposure requirements and cannot be damaged by cleaning solvents, UV light, or normal use.