The 811 is a double cone/barrel shaped medium grit diamond bur used for occlusal/lingual reduction.
With its larger diameter, the 811 is an alternative to using football-shaped diamonds when making larger occlusal adjustments.
Occlusal / palatal reduction medium grit, FG 314 diamond. Head diameter 033 (3.3mm) with working length 4.3mm. Maximum recommended speed 100,000rpm.