That's the slow PIII 550. There were 3, yours (slot 1 with 512k half-speed cache), plus a Slot 1 and a Socket 370 version of the Coppermine (256k of full-speed cache). The faster cache was a lot better than simply having more slow cache.
That CPU will work in ANY Slot 1 board that supports 100MHz bus, including BX chipset boards, which were the most common back then.
Some boards require a BIOS update to properly recognize the CPU.
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