The collets and collet nut for the Spindle No. 5.
The 6.0-mm collet is included in the Spindle No. 5 or the Kit No. 5 by default.

The collet's nominal diameters are the maximum dimensions to be held.

Note that when the difference between the shank diameter and the collet's nominal diameter increases, the runout will also increase.

For example, the 6.0-mm collet can hold the 5.5-mm shank, but not the 6.3-mm shank.
The accuracy will become low with the 5.1-mm shank.
Use the 5.0-mm collet for the shank diameters of 5.0 mm or less.

Note that these collets require a long lead time.