Check the listing for details. 512KB 15+12ns Cache SRAM Kit for 486. Listed at 26.00 USD. 512KB cache SRAM kit for 486 and Pentium machines. Tested. Beware of fake SRAM. I also have single SRAM ICs for sale, and can make up different kits. This listing is for:4 x 128K*8 15ns IC (DIP-32) 1 x 32K*8 12ns IC (DIP-28) Your motherboard may need another a different combination of chips for 512KB.Ask if you need different ICs and I can make up a custom kit for you (512K, 256K, etc). Check your motherboard manual or TheRetroWeb for the required cache ICs and jumper settings. --- 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.