One of the fastest 486 CPUs you can get, for Socket 3 motherboards that support it.
This requires 3.45V or near that. Do not install it into a motherboard that provides 5V to the CPU, and make sure your jumpers are set correctly.
This CPU requires a heatsink.
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eBay doesn't allow custom shipping service names.
"Economy" will be tracked airmail to most countries, but untracked to a few more remote ones. 1-2 weeks usually, but can take longer.
"Expedited" will be DHL Express. 3-4 days usually. Exact quotes vary depending on the country. I can refund if you are overcharged.