IP44 or IP65 for spotlights in bathroom and what does 'Outside Zone' mean?

[obsessedwithinteriors]

I am having my ceiling taken down and new spotlights put it. I was hoping to buy these, but not sure if I need IP44 or IP65? It also says Outsize Zone on the description, but not sure what this means (even after googling!) www.screwfix.com/p/lap-fixed-downlight-integrated-led-chrome-1-92w-240v-pack-of-3/50248?kpid=KINASEKPID&cm_mmc=AffiliateWindow--Comparison+Engine--Datafeed-_-38953&source=aw&awc=1228_1425766592_c20c4f93b102f391f31ca5f687e8e0e9

Thank you.

This article explains bathroom zones for lighting

Thanks, better get IP65 then to be safe.