Excellent and handy sanding disc that fits direct onto your lathe chuck.
Dovetailed recess in the back is 55mm that fits most standard 4" chucks and jaws, inc super nova, record sc4,vicmarc etc. Not suitable for axminster c jaws.
The disc is actually 145mm so that the 6" sanding sheets easily fit onto it. Just use a pair of scissors to trim the abrasive onto the disc!
Can also be used to hone the edge of some tools. It works
especially well with a skew to get a razor edge. I use 400 grit.