Cheap replica of some 3-day assault pack with MOLLE attachment system, adapted and enhanced by owner as much as his creativity allowed. Does not offer much comfort, and volume is far lower than that of a proper 3-day pack, but it's still a backpack alright.
The Backpack spawns in the flash drive campsite by the two story dorms. It can be found leaning on the side of the tent.
Bottle of water (0.6L)
Flyye MBSS backpack
|→||Lavatory level 1
The Scav Backpack appears to simply be a Flyye MBSS Backpack in an olive drab color and customized with various accessories attached to the pack, including a compression sack, foldable sleeping pad, what appears to be a first aid kit, a water bottle, and some carabiners.