The apple core burr on the long unguarded shaft has several major benefits. It can be used for buffing sharp canine teeth, and for contouring the upper and lower 06s.
Its biggest application is being able to get caudo-buccal sharp enamel points on the 11's in small and tight mouthed horses such as minis.
Also compatible with this shaft: chamfer burr (regular & small), apple core burr (large), diastema burrs - conical, tapered, periodontal, slimline.