The NTSNEC1200HK is likely designed for use in electrical systems, perhaps for power distribution or protection purposes. It may offer specific features or performance characteristics that make it suitable for certain industrial or commercial applications.
SY100K250D
It may be a variant of the NTSNEC1200 series. It could have similar characteristics to the other models in the series regarding voltage ratings, capacity or rating values (possibly related to current or power), and would likely meet relevant international safety and performance standards.