Under Armour - Hustle 6.0 Backpack. Color Castlerock Full Heather/Black/Black. On sale for $44.21. MSRP $55.00.. Add to favorites. 0 people have favorited this+14Brand NameUnder ArmourProduct NameHustle 6.0 BackpackColorCastlerock Full Heather/Black/BlackPrice$44.21MSRP: $55.00Rating