This is a  unification of the properties of MACH I and MACH III in the form of a combination shoe.  The MACH III is used for the cam end block and the MACH I is used for the anchor end block.  The performance is reduced to 23, 000 lbs but with improved heat performance over the   MACH I.  This combination is suitable for on and off highway applications where foreign aggregate is still prevalent and/or where duty cycles are heavy.  Friction is more consistent than MACH I with less fade and responsive friction recovery.  The high heat durability of the MACH III cam block provides for maximum break life in the environment that the products were designed for.