105x617 nato tank shell casing

105x617mmR NATO-standard brass tank shell casing. 

• Caliber & Length: 105 mm × 617 mm (diameter × length).
• DM60: Denotes the specific German military designation for this type of brass cartridge case.
• LOS: Short for Losnummer (German for lot number).
• DN-7-28: The manufacturer's production code and batch tracing information 

These casings were commonly used with the Royal Ordnance L7 and M68 series rifled tank guns, which are featured on Cold War and modern main battle tanks such as the German Leopard 1 and early U.S. M1 Abrams. 
Info taken from online as I don’t know to much about it . Cool military collectable 

$125