 "Pontoon System" gives more buoyancy to float on water when additional weight is put on to the vehicle.The average cost per unit is approximately ₩3.95 billion ($3.5 million USD) (2015).Doosan DST and Belgian firm Cockerill joined together in early 2013 to develop the Cockerill XC-8 turret for the K21 to provide a medium weight direct fire capability.