Markerlight
A Markerlight is essentially a laser targeting system wielded by Tau infantry, mounted on a weapon, carried by a drone and aimed like any other weapon.[1][2][4]
Overview
The markerlight itself does no damage, but instead provides targeting information to other Tau units and vehicles. This increases the effectiveness of other Tau units firing at the "lit" target. In addition, the markerlight can be used to give a squad instant support, as when a markerlight is fired, a signal can be sent to a remote Seeker Missile mounted on a vehicle to seek out the painted target and destroy it, completely independent of the vehicle. Each Markerlight has its own unique pulse pattern, which is transmitted to the Seeker Missile's guidance controls prior to launch, to ensure the missile follows the correct beam to its target.[3]
The only downside is that while invisible in normal conditions, it becomes visible when it passes through dense airborne gas or vapour (such as smoke or fog) and in so doing risks giving away the user’s position.[4]
Networked Markerlight
A Networked Markerlight is a markerlight that also provides targeting information to the squad that fires it.[2] It is networked directly into weapon systems.[5] This has the advantage that a squad utilizing a Networked Markerlight can gain its benefit (unlike the standard markerlight).[2][5]
Images

See Also
Sources
- 1: Codex: Tau (3rd Edition), [Needs Citation]
- 2: Codex: Tau Empire (4th Edition), [Needs Citation]
- 3: Imperial Armour Volume Three - The Taros Campaign, pg. 178
- 4: Deathwatch: Mark of the Xenos, pg. 5
- 5: Codex: Tau Empire (7th Edition), pg. 123, Networked Markerlight
- 6: Games Workshop Tau Pathfinder Team (last accessed 3/16/2021)
- 7: Codex: Tau Empire (6th Edition), pg. 82