This "cerametallic" clutch disc fits Tilton OT-II 7 1/4" rally clutches. The special ceramic/metallic friction material allows better slippage and modulation to deal with tricky dirt and gravel roads on special stages. The 29mm x 10 spline (actually 28.58mm x 10 spline) is found on many BMWs, as well as some ZF and XTrac gearboxes. Sold individually.
Tilton's minimum recommended disc thickness is 0.253" in single-disc rally clutches or 0.268" on dual disc rally clutches. New cerametallic clutch discs measure 0.283" thick.