They all have Sennheiser advanced audio technology, plus a new design of earphone capsule with special damping and tuned to provide a natural balanced sound with good bass and treble reproduction.
The MX 90 VC Style earphones cost £49.99 and feature 'twist to fit' system allowing them to be easily moulded to fit the shape of the ear, particularly during active movement thanks to the small stopper that twists into place in the outer ear. The volume control is on the cable.
The OMX 90 VC Style at £44.99 feature aluminium bows with different height adjustments, and built-in volume control on the cable.
Finally, the LX 90 Style come in the cheapest at £34.99 and come with a self-configuring headband - a thin flexible plastic tube with a metal core that will adjust as necessary.
A good range of options for those who like earbuds over headphones, from a quality manufacturer.