One key includes 9 items of DLC only.
Frontline Tactics - Sniper
Frontline Tactics - Close Quater Combat Soldier
Frontline Tactics - Medic
Frontline Tactics - Golden Guns
Frontline Tactics - Ninja Camouflage
Frontline Tactics - Woodland Camouflage
Frontline Tactics - Desert Camouflage
Frontline Tactics - Snow Camouflage
Frontline Tactics - Tiger Camouflage

These require the base game which is free-to-play on Steam:
http://store.steampowered.com/app/218310/Frontline_Tactics/

Key from the Bundle Stars Dollar Rage bundle. No thanks necessary. Good luck