Standards are rat fur, my old Markbass 106 STD was rat fur, mind you it was old school Markbass with the silverface logo and normal looking drivers, their current standard line might be tolex and I haven't seen a current 106 or even seen a 108 although I know they do exist out there in the wild.
Carvin LB76 / Dingwall ABZ ! Support Local !
MarkBass SD 800
Epifani UL2-310 / fEARful 1212/6
! Rocking against all gods !