The Resonant Satchel is an item added by Thermal Expansion 4. It is a portable bag that can store 36 items.
Resonant Satchels can have Signalum Security Locks installed on them to configure who may access their contents.
To prevent creating infinite storage, as well as some world-corrupting issues, Satchels cannot store items that can also store items themselves, like other Satchels and Strongboxes.