Brass Ring with 10mm Female thread 
This Brass Ring is perfect for hanging lampholders from chain.
This can be used at either the lampholder end or the ceiling plate end.
If you want to use this with a lampholder then you will need a small piece of male thread to go in between this and the lampholder.
For a ceiling plate end you will need something like a pottery nipple PLU86986 or PLU71601
Thread: 10mm x 1mm pitch
Outer Ring: 40mm
Inner Ring: 30mm