Well I can't help you with a 6 inch chuck i'm afraid but I do have a zither 4 jaw, in the 4inch size. and I can commend the nice quality of it.
The Zither is the one in the middle, the other one is 8 1/2inch 4 jaw.

I think Neil the editor has a zither as well, possibly the same.
Unfortunately it's a face-on image so it doesn't show you the depth. But it is of course, significantly thinner than it's bigger brother. The intention of having so many is to handle different sized work, as i'm sure you all know how insensitive the larger ones can be when handling delicate or smaller work.
Michael W
Edited By Michael-w on 05/03/2017 19:54:06