When i buy carts the packs need to be sealed, also if the carts are made in USA, Germany or UK with "old" style graphics/packaging then you can be pretty sure its NOS.Sensor shave 12, and last, no irritation, but not as close as I prefer.
may be a foolish question, - how do you ID NOS carts? Lookin for Sensor and Atra--do you accept seller claims on the bay?
The only time ive accepted an open package is because it was part of a larger order where most of the packs were sealed and 2 were open but included all the original packaging (the glue had deteriorated)
I think @Sabre can give a clearer answer than me on these.