No I am on about prommy blue, I am not that stupid. Its been a long standing issue of people complaining about the results and the purple has become the standard one. I didnt see any difference between the two regarding accuracy but the blue just fell apart. Dont know what the difference between the rubber compounds is, I am not a rubber expert but they are definitely not the same.
It might be something prommy have fixed now as that was a while ago but everybody still goes for the purple.