Rayco Transformer?

Hi, does anyone know anything about this bit of equipment? I was looking for a voltage stabilizer and came across this but couldn't find any information online about it. Is it just a transformer or a stabilizer too?



Thanks

It's a stabiliser:
https://www.profilmdirect.co.uk/rayco-240v-voltage-stabiliser-3746-p.asp

Thank you Alan for the help