The Backpack Expander is a tool item that appears as a backpack held together with four straps that has a Description Tag, Heavy Duty Rag, two Mann Co. Supply Crate Keys, and three Huntsman arrows protruding from it, along with a Sandman strapped on top. When used it will grant 100 extra slots, or two full pages, to the user's in-game backpack. Multiple Backpack Expanders can be used by the same player to obtain a maximum of 2000 slots (40 pages). Free-to-play players can use up to 19 Backpack Expanders. Premium players can use up to 17 Backpack Expanders.
December 17, 2010 Patch (Australian Christmas)
- [Undocumented] Added the Backpack Expander.
November 21, 2012 Patch
- Increased the maximum size of backpacks from 1000 to 2000.
May 17, 2013 Patch
- Backpack expanders are on sale for 80% off.