Sounds like you are referring to MAT files supplied with say... a clothing item...

Vendors often supply several options of the same MAT for the various versions of Poser. They have to provide differen MAT files for each version as things changed along the way with the way the different versions handle materials.

If... you are using P6... then your best option is to select the P5 Mat files as that will be the closest in compatability to P6 and should work okay.

P4 users would use the P4 MAT and PPP users the PP Mat and so on...

Hope that makes sense...

"You don't have to be mad to use Poser... but it helps"