1/2-inch Mount or P-Mount?
This cartridge is available with either a 1/2-inch Mount or a P-Mount. You will almost certainly need the 1/2-inch Mount version. That will allow it to be fitted to all quality tonearms with the two mounting points on the head shell. The P Mount version (also known as T4P) is for plugging directly into specialised tonearms with a squarish receptacle on the end. If in doubt, choose 1/2-inch. You can learn more about this here.
The newly redesigned Blue1 and Red1 have had their coil design reconfigured, and the effective moving mass of their generating system has been reduced by 17%.
The Blue1 and Red1 models use a four piece OTL cantilever technology, standard oxygen free wire in the coils and Grado's specially designed elliptical diamond mounted on a brass bushing. The Red1 model is selected from the Blue1 production run and meets higher test specifications. Approximately 10% of the production run will meet these standards and become Red1 models.