Features:
The 2M Blue features a Nude Elliptical diamond and split pole pins with a copper wire.

Designed for easy mounting of the cartridge, and for the weight and size to fit the most common turntables on the market today. The 2M Series provides excellent compatibility when used in an assortment of playback systems and with a wide variety of phono preamps.

The 2M Blue adds more dynamics and resolution, sounds more open and reproduces more details compared to the 2M Red model.

2M Blue Technical data

Replacement stylus unit - 2M Blue (interchangeable with 2M Red and 2M Silver)

2M Series styli interchangeability:
The 2M Series' engines, coils and magnets configurations are not identical: Red and Blue are identical, so are the Bronze and Black and so are the true mono variants 2M Mono and 2M 78. Likewise, 2M series styli are interchangeable within the below combinations:
- 2M Red, 2M Blue and 2M Silver
- 2M Bronze, 2M Black and 2M Black LVB 250
- 2M Mono and 2M 78

Compatibility with Rega brand TT/TA:
REGA brand cartridges’ height from stylus tip to the top cartridge mounting surface is lower than standard. Therefore you would need spacers to ensure the correct set-up of the Ortofon cartridge. 
Adjusting the height of your Rega tonearm is easy with Acoustic Signature's Spacer Set. It allows you to adjust the height from 0.5 mm to 3.5 mm in precise steps of 0.5 mm - without removing the tone arm. Simply loosen the screws, insert the AS-spacer, then lock the screws back down, and you're tonearm is ready to play.
3.2 - 4 mm spacers should be enough for 2M cartridge.