Weldon type 3/4″(19,05 mm), incl. collet Nut.
The Phantom ER 25 Collet Chuck is used with separate ER 25 Collets.
Dimensions between 5 and 6 mm can be clamped using, for example, a 6 mm ER 25 Collet.
The collets are available separately in dimensions of 1 to 20 mm.