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.
The event MON810 produces a Bt toxin against lepidoptera (European stemborer and other moths/butterflies); MON88017 is a stacked event with glyphosate herbicide tolerance and a Bt toxin against coleptera (corn root worm and other beetles).
As an F1 hybrid of two deregulated GMOs it is not regulated in the US. MON88017 x MON810 has environmental, food and feed approvals in a number of countries, mainly in Asia and in Mexico.