The Boehler Almax design anvil was optimized for supporting its crown section. It requires a very well precisely-matched tungsten carbide backing plate. Boehler, R. (2006). Rev. Sci. Instrum. 77, 115103.
All type IIas anvils are Raman ultra-low fluorescence and ultra-low birefringence, (100)-oriented and particularly suitable for IR and highly demanding Raman spectroscopy.