Brian kindly left this comment under Christmas #2. As it is chock full of useful Dremel-related miscellany, I am republishing it as a post, with his permission of course. Here it is, with a few minor modifications (and with a few comments from me in italics):
EZLock now has an extended range & overseas readers may find the SpeedClic info helpful.
EZ495 EZ Twist Nose Cap
Note: (As discussed here) collets have the advantages of better grip & less of the tool sticking out vs the chuck. That reduces vibration. If you use Router Bits in a chuck they often come loose.
The EZ Twist is just a new Nose Cap for the 4000 & older Dremels. It is used instead of the flat metal 90962 Wrench (spanner) to tighten & loosen the black Collet Nut & the silver Driver Cap or Driver Adapter used for the Flex Shaft (225), Mini Saw (670), & Right Angle Attachment (575).
I can say that the new EZ Twist Nose Cap works great. It can be retrofitted to most existing Dremels & just replaces the existing nose piece. It isn’t very expensive either at under $10. I have used it on a 395 Multipro as well as the 4000.
To use it you just unscrew it. It comes forward off the mounting thread & then the internal socket fits onto the Collet Nut to allow you to loosen or tighten it. You don’t have to take it off the neck of the tool to use it. Just slide it forward enough to fit the Collet Nut.
Simple & easy & nothing to go wrong.
Great that you can “upgrade” an older tool