The Sub Detection Unit is a new collectible in Genshin Impact 4.1. You have to farm lots of units to ascend the upcoming character Wriothesley. Here are the best farming routes for this collectible.

#1. Liffey Region

Liffey Region is a new area in Fontaine 4.1 that is right above the Court of Fontaine in the minimap. Unlock the Statue of Seven in this region and start your farming route from this point.

  • Grab four units on the platform of the Statue of Seven.
  • Head toward the waterfall in the south of Mont Esus East to grab two units on the upper platform and another on the lower platform.
  • Next, glide or swim to the farthest island from the fall to capture one.
  • Then, travel along the path to the tower in the north and you will grab three other units.

Use Mona or Ayaka to sprint to the tower location faster as there isn't any waypoint near the tower.

Liffey Region
Collect easy sub-detection units in the Liffey Region.

#2. New Fontaine Research Institute

The area of New Fontaine Research Institute is larger. Therefore, you can farm more Sub Detection Units for Wriothesley. Here are some farming routes in this region.

  • Traverse along the coastal line;
  • Explore around the outer ring of the New Fontaine Research Institute;
  • Climb broken walls in the area of the ruins;
  • Visit mountain ledges around the institute;
  • Head to the tall town in the North of the Central Laboratory Ruins;
  • Teleport to the northeast waypoint in the Central Laboratory Ruins and head south to collect Sub Detection Units on two banks of the river.

It's easier if you start farming from a high spot and glide downwards.

Fontaine Research Institute
The New Fontaine Research Institute area has lots of collectibles.

#3. Mary-Ann Memorial Park Route

You should start your Subdetection Unit Mary-Ann Memorial Park farming route from the Statue of Seven in the Fontaine Research Institute of Kinetic Energy Engineering.

  • Under the broken parts of bridge ruins;
  • Around the platform of the Experimental Field Generator
  • On the top floor of the next building.

You can farm lots of sub-detection units on the way connecting two Statues of Seven in the new map. Don't forget to use teleport waypoints to approach the location of Subdetection Units quickly.

The Last Area Above Ground
It's easy to farm this material on the Mary-Ann Memorial Park route.

#4. Underground Locations

You can find two collectible units in the North of the Abandoned Production Zone of the Fortress of Meropide. Then, access Kuisel's Clockwork Workshop and collect these units at the Entrance, Middle Level, and Lower Level.

Besides, enter the Ruins and Lower Ruins of the Abandoned Laboratory to farm more collectibles. These Subdetection Units in all locations above will respawn after 48 real-life hours.

Underground Collectibles
Locations of all underground collectibles

There are some non-respawn Subdetection Units in a Hilichurl camp in the northeast area of the Kinetic Energy Engineering Region. You can find this camp on a northern ledge from the teleport waypoint on the lake bank. Farm at least 68 units before the release of Wriothesley.

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