LEDVANCE's wall lamp requires one bulb. This lamp is made for indoor use and 18W is the maximum recommended wattage for bulbs.
From ManoMano
080034 Led porthole Ledvance 350 18w 4000k ip44 1440lm - Osram
LED Bulbs
Ledvance 18W LED Surface Steel IP44 Cool White - SC35040-080034
Big on Electricals
Ledvance 18W LED Surface Steel IP44 Cool White - SC35040-080034