Pro Series by HHIP 3900-0689 Collet Chuck Nut, Um-Type Er20, 18000 RPM, M25 x 1.5

Collet nut worked great did need to manually grind a chamfer in the top of nut to increase ease of engaging the nut to spindle.

Had No vibration with this nut. The collet snaps in perfectly. Just to remind people ER collets need to be inserted properly, if you need to unscrew the nut twice to release the bit your collet is not snaped in properly. I recommend this Nut

My fingers and thumbs are sore from fighting with this collet nut when installing and removing collets. It's also frustrating to thread it onto my lathe spindle, it just refuses to engage with the threads until you hit the one tiny spot where it locks in, never seen anything like that.Maybe I just got a bad one, either way, it's being returned.