Type H vs. Type O

Type H is Israel's own standard, used almost nowhere else -- one of the most geographically limited plug types in the world. A 1989 round-pin revision replaced the original flat-pin design, and modern sockets accept both, plus the ungrounded Europlug.

Type O is Thailand's standard, introduced in 2006 -- three round pins whose earth-pin offset happens to numerically match Type B's, letting Thailand's real-world hybrid sockets also accept American Type A/B and European Type C plugs. Pure single-standard Type O outlets barely exist in practice.