NK603 is one of Monsanto's maize events sold as "Roundup Ready". It contains two copies of the cp4-epsps gene transfering glyphosate tolerance. The transgenes are controlled by two different promotors, on of which the enhanced CaMV 35S promotor, the other a rice actin promotor. The event was developed by biolistic transformation, i.e. gene gun, using one construct that contained both copies of the herbicide tolerance gene.