If the Natural Ergonomic keyboard works for you, why not put in an eBay search and buy a spare or two? Even one new in box is unlikely to cost more than a curr

If the Natural Ergonomic keyboard works for you, why not put in an eBay search and buy a spare or two? Even one new in box is unlikely to cost more than a current alternative if you are a little patient. Since you mention "wired" there are boatloads of 4000's on the market all the time. Good luck.