Centon MR20 ringflash

Hi all,

anyone know much about these? There are a couple going cheap (compared to retail) on ebay, and with the nights drawing in, I thought I might have a bash at macro with one of these. My main lens for macro has a 62mm thread. Will I lose much of the image coming down. I can't find out exactly what thread the flash has.

Cheers

Liam