This LED is specifically designed to be in the nominal 660nm wavelength range.  This Cree XP-E is mounted on a direct thermal path copper MCPCB, which allows for higher drive currents, cooler running, and longer life.  A great driver to use with this LED is the 17mm Nanjg ak47a .

CREE XP-E Red (wavelength range: 650-670nm; average 660nm)

• Maximum Recommended Drive Current: 1900mA (1.9A)