The switches of the MSM family retain the original 19, 22 or 30mm diameters, and stainless steel or aluminium housings, but have changed in two places, both involving the illumination:

• Ring illumination is more even – “by cleverly selecting a new material that diffuses the light much more widely”, according to the firm. “The LEDs used for ring illumination are no longer individually visible, one can truly speak of homogeneous illumination.”
• Ring illumination is better proportioned – the ratio of housing diameter to the width of the illumination ring has been redesigned, said Schurter “resulting in a more pleasant, scaled appearance”.

Toughness has not changed: sealing is still to IP67 and they have IK07 impact resistance.