The very first consoles were fitted with P&G faders as this is what was used with the XL8.  The MKT fader was developed and a gradual introduction of these faders into consoles was made.  Apart from the XL8 that has to use P&G moving faders, all other Midas consoles now use the MKT fader.  If a P&G fader requires replacing, then an MKT fader can be used in its place (apart from XL8) and no noticeable difference will be seen in the fader movement.