Sockets in Luxembourg: Types C and F, supplied with 230 V at 50 Hz. At 230 V the supply matches what UK and European appliances expect, so no converter is needed.
The same socket system is used in Hungary, Iceland, Türkiye and Estonia, so one adapter covers all of them. Nearby but different: Malta, Ireland and the United Kingdom – an adapter for Luxembourg will not fit there. 31 of the 50 destinations in Europe share the plug types of Luxembourg.
Protective earth
Grounded and ungrounded sockets may occur
Not every socket in Luxembourg is earthed: Type F yes, Type C no. Class I appliances belong in an earthed outlet.