I purchased from Prazi "ER-25 Super Precision Chuck and Spanner Wrench (MT2 Only)"
from << http://www.ismg4tools.com/prices/Pricelist_for_D6000.htm >>.
The reason I chose this set was on the recommendation of a tool & die maker's advice.
On my Atlas 618 I used my DTI on the Prazi set versus a...