What's the most waterproof headlamp here?

Waterproof ratings in this pool top out around IPX5 (Blukar), with most others rated IPX4, meaning they handle rain and splashes but are not built for submersion. If you expect heavy downpours or water sports, prioritize the higher IPX rating and note that none of these candidates advertise full submersion (IPX7/IPX8) protection in the supplied data.