Equipper
From Inkipedia, the Splatoon wiki
The Equipper is a mechanic in the Octo Expansion.
It is a metallic pad with shoe prints printed on top. Activating the Equipper raises a glass cylinder with rotating metal plates, while a menu is shown with one to three weapon loadouts - sets of main and/or sub weapons, a special weapon, or an unarmed option. Choosing a loadout selects it for the next mission or section.