Wall Gaugeウォール・ゲージ

Measures the thickness of the wall behind it, though its hand fluctuates.
In-game description

What you get from salvaging Wall Gauge (Salvage and Repair Station)

Wall Gauge can be salvaged. Salvaging it gives the following items.

For each material, the amount is "amount used to craft × 0.49 (lower when durability is down, 0.3 at 0 durability) × the item's multiplier", and a fraction is the chance of one more (2.4 means 2, with a 40% chance of 3). The range is from 0 durability to full durability (items without durability always count as full). Scrap parts are a fixed number set by the item level. All items that can be salvaged are listed in salvaging.

How to get Wall Gauge

Placed inside dungeons or scenes (buildings, ruins and so on); break it or pick it up to get itPlaced in: Excavation Double Path [Breaker's Reach], Excavation Doorway [Breaker's Reach], Excavation Hallway, Excavation Storage [Breaker's Reach], Excavation Town Square [Breaker's Reach], S.A.H.A.B.A.R. Monument (style 2) [Breaker's Reach] and 1 more

Scene containers, dungeon placements, guaranteed drops and natural spawns are based on the Obtaining data of the Core Keeper Wiki (Fandom) (CC BY-SA 3.0), because these are not in the game files this site reads. Scene names are the wiki's English names.