Allows binding items permanently to players without consuming inventory or equipment slots (by way of API, commands, or the Impartment Contract item). Bound items will always be in effect for the player. Configurable.

To acquire Impartment Contracts, you must find the Wandering Ghost NPC. He rarely spawns in the underground, and will accept rare item trades for Contract Tatters. You can craft 3 tatters into 1 Blank Contract, and then drag and drop an item onto it to craft an Impartment Contact, which may be used freely.

https://forums.terraria.org/index.php?threads/intrinsics.80322/