Mass of Iron Bolts

Mass of Iron Bolts is a 3-Star Iron-type Material for developing and upgrading weapons and armor at Chokufunsha.

Locations
As a 3-Star Material, Mass of Iron Bolts will mainly appear in Crowley's Area (21-30F).

May also be obtained at Gyaku-Funsha shops, as a reward from Lost Bags, and appear in the daily Hernia lineup.

All-material floors will spawn every type of material, but only of the same level as the area (Max's Area will spawn 1-Star materials, Jackson's will spawn 2-Star, etc). Material-specific floors will only spawn one type of material, but they can spawn as the same level of the area as well as 1-Star above and 2-Stars below. Fiber materials are an exception, and 1-5 Star Fibers will show up on any floor that can spawn Fiber, regardless of the area. Certain floors may not always appear, based on tower rotation. See this spreadsheet. Some floors don't spawn any materials at all.

Floors in  Bold  are connected to the main elevator.

Uses
NOTE: Tier is a level of power typically based on the number of times equipment has changed forms, not the number of stars it has.